2016.06.21 gmm csic NanoFrontMag

MAGNETIC NANO & MICRO WIRES

Manuel Vazquez

Group of Magnetic Wires .

Institute of Materials Science of Madrid, CSIC. Spain

1.5 mm metallic diameter

AUTOR/ES TÍTULO FECHA TIPO REVISTA CAPÍTULO PÁGINAS COMENTARIO

C. Bran, E.M. Palmero, Zi-An Li, R.P. del Real, M Spasova, M Farle and M

Vázquez

Correlation between structure and magnetic properties in CoxFe100-x nanowires: the roles of composition and wire diameter

2015 Article J. Phys. D: Appl. Phys. 48 145304 (7pp) Col. Duisburg-Essen

Univ.

C. Bran, A.P. Espejo, E.M. Palmero, J. Escrig and M. Vázquez

Angular dependence of coercivity with temperature in Co-based Nanowires

2015 Article J. Magn. Magn.

Mater. 396 327–332

Col. Santiago Chile Univ.

J.G. Ovejero, C. Bran, M.P. Morales and M. Vazquez

Electrochemical synthesis of core–shell magnetic nanowires

2015 Article J. Magn.Magn. Mater. 389 144–147 Letter to the Editor

Belen Sanz, Ester M. Palmero, Rafael P. del Real, Manuel Vazquez and

Carmen Mijangos

Arrays of Magnetic Ni Nanowires Grown Inside Polystyrene Nanotubes

2015 Article Ind. Eng. Chem. Res. 54 13005−13008 Coll. ICPM/CSIC

M. Vazquez, R. ElKammouni, G.V. Kurlyandskaya, V. Rodionova and L.

Kraus

Bimagnetic Microwires, Magnetic Properties and High-Frequency Behavior

2016 Book Chapter “Novel Functional

Magnetic Materials”, A. Zhukov (ed.)

7 29 pag.

Springer Series in Materials Science

231, DOI 10.1007/978-3-319-26106-5_7, Springer

International Publishing

Switzerland) 2016

M.S. Arshad, M.P. Proença, S. Trafela, V. Neu, U. Wolff, S. Stienen,

M. Vazquez, S. Kobe and K.Ž. Rožman

An oblivious growth mechanism for high-magnetic-anisotropy hcp Co-Pt nanowire

arrays: the role of the crystal orientation in the switching-field distribution and the

magnetic-domain configuration

2016 Article J. Phys. D: Appl. Phys. in the press Coll.

Slovenia Univ

Alejandro Jiménez, Peter Klein, Rastislav Varga, Rafael Pérez and

Manuel Vázquez

On the induced voltage by the domain wall propagation in cylindrical magnetic

microwire 2016 Article IEEE Magn Letters

Submittted Coll. Kosiçe Univ

M P Proenca, C T Sousa, J Ventura, J Garcia, MVazquez and J P Araujo

Identifying less-interacting single domain states in Ninanowire arrays by FORC

2016 Article J. Phys. D: Appl. Phys. Submitted; Coll.

Porto Univ.

Lei Shao,Yangyong Zhao, Alejandro Jiménez, Manuel Vázquez, Yong Zhang

Shape memory and huge superelasticity in Ni-Mn-Ga microwires

2016 Article Metals

Submmitted; Col. University of Science and

Technology Beijing

AUTOR/ES TÍTULO TIPO CONFERENCE FECHA LUGAR A. Jimenez, R. Varga and M.

Vazquez

Electromotive force indiced by domain wall propagation in

magnetic microwire

Oral Presentation

INTERMAG'2015 13/05/2015 Beijing, China

M. Vázquez, C. Bran, A. Asenjo, R. Perez, E. Palmero, Y. Ivanov and O.

Chubykalo-Fesenko

On the magnetization reversal of Co based nanowires

Invited Presentation

Int. Worksh. Magnetic Nanowire and

Nanotubes 19/05/2015

Meersburg, Germany

A. Jimenez, R. Varga, R. Perez and

M. Vazquez

Controlled motion of single Domain Walls in magnetic

microwires


7th Int. Workshop on Magnetic Wires

02/07/2015 Ordizia, Spain

M. Vazquez Program

Committee Chair

International Conf. on Magnetism, ICM

5-10 / 07 / 2015

Barcelona, Spain

C. Bran, E. Palmero, E. Berganza, R.P. del Real, A. Asenjo and

M. Vazquez

Co-based cylindrical nanowires: from applications of their arrays to

the spin reversal of individual nanowires


NanoPyme Workshop on Rare-earth free

permanent magnets and applications

14/09/2015 Madrid

M. Vazquez, C. Bran, E. Palmero, E. Berganza, R.P. del

Real, A. Asenjo

Magnetization reversal of Co and CoFe-based cylindrical nanowires


Amorphous and Nanostructured

Magnetic Materials, ANMM’15

23/09/2015 Iasi, Romania

R. Perez, E.M. Palmero, C. Bran and M. Vazquez

Magnetic nanowires used in magnetic pick-up senswors

Oral Presentation

2016 MMM/INTERMAG Conf.

12/01/2016 San Diego, USA

M. Vazquez CoFe based nanowires and their

technological applications Inaugural

Invited Talk

3rd. Int. Conf. on Recent Trends in Physics, ICRTP,

13/02/2016 Indore, India

AUTOR/ES TÍTULO FECHA TIPO PUBLICACIÓN

DIRECTOR/ES COMENTARIO

Rhimou El Kammouni

Single and Biphase Magnetic Microwires: Microwave

behavior and temperature dependence

2015 (Abril) PhD Thesis, UAM M. Vazquez Tutor: M.A.

Ramos

Sobresaliente cum laude

unanimidad

Alejandro Jimenez Villada

Dinámica de la propagación de una única pared de dominio y

procesos de imanación en microhilos magnéticos

2016 (22 Enero)

PhD Thesis, UAM M. Vazquez Tutor: M.

Hernández-Vélez

Sobresaliente cum laude

unanimidad

Ester M. Rodriguez Palmero

2016 (Noviembre)

M. Vazquez & R. Perez

Joe Angel Fernandez

2018 (Mayo)

M.Vazquez & R. Perez

& O. Chubykalo


1.- Magnetic Nanowires:

Synthesis of CoFe with controlled anisotropy

Nanowires with modulated diameter & Core/shell nanowires

2.- Magnetic Mcrowires:

FMR in biphase microwires

Controlled motion of single Domain-Wall in single phase microwires


-Looking for specific cylindrical nanowires & arrays - Arrays ar relevant for 3D magnetic architectures, sensor devices, novel magnets, biomagnetic functionalization and beyond - Individual nanowires are nearly ideal systems for fundamental studies on magnetization & reversal - Why Electrochemical route of fabrication? Less-expensive technique Ability to grow various cylindrical nanowires with designed geometry and composition periodical modulations

- Why cylindrical symmetry nanowires? Nanoscale systems profiting of strong shape anisotropy (Diameter: 15nm to 200nm; Length: 100nm to 50mm) Nanocolumns,Nanotubes,Multilayer,Diameter-Modulated, Core@Shell

- Combining magnetic (Co, Fe) elements & alloys to tailor structure and magnetocrystalline anisotropy so magnetic response

Designed Cylindrical Nanowires: Overall Motivation

Self-assembled pore template

CoFe nanowire array

1.- Uniform/straight Nanowires:

Nanodots, Nanowires (reduced diameter)

2.- Modulated Nanowires :

a) Longitudinal

Multisegmented, Multilayer

b) Radial

Nanotubes, Core/Shell

c) Diameter Modulated

Co/Cu multisegmented

Ni nanotubes Fe&Au core&shell

CoFe diameter modulated

Families of magnetic nanowires prepared by electrochemical route at ICMM/CSIC, Madrid

CoFe homogneous

Removal of alumina

Au layer sputtering

NWs growth

Removal of barrier layer

Al foil

Removal of Al layer

1st anodization

2nd anodization

Potentiostatic electrodeposition

Synthesis procedure: AAO template + metals electroplating

Al disk and inner electroplated region

NWs released from the membrane

Anodic Aluminium Oxide, AAO, membrane

FeCo NWs

Correlation Magnetic to Structure characterizatics

FeCo alloy nanowires

40nm diam. 20 nm diam.

For 40 nm wires, structure evolves from bcc to fcc as the Co% increases For 20 nm wires, it evolves as bcc->fcc->hcp

Role of Composition and Nanowire Diameter

HRTEM characterisation of individual Co nanowires

Single crystal [111] fcc Co nanorod

X.X. Zhang, KAUST

Single crystal hcp Co nanorod

fixed diameter, D=35nm and length, L=3mm

Textured along different directions in hcp-phases with pH of synthesis

Co nanowires: Crystal structure and Magnetic Anisotropy

TEM study of Co nanowires prepared under different electrolyte pH: (a) – pH 3.5, (b) - pH 5.0, (c) – pH 6.0 The insets show the corresponding electron diffraction patterns and HRTEM images The green arrows show the orientation of the c-axis. The white arrows indicate the crystal orientation

Co nanowires: Crystal structure and Magnetic Anisotropy

Yu.P. Ivanov et al. Nanotechnology 2014

Hysteresis loops & Spin imaging: VSM & SQUID vs. VF-MFM & MTXM

-100 -80 -60 -40 -20 0 20 40 60 80 100

-1.0

-0.5

0.0

0.5

1.0

Mr/

Ms

B(mT)

Ciclo SQUID

Ciclo MFM

MFM imaging of Ni nanowires (d=180 nm, L = 2 mm)

A. Asenjo et al. PRB 2007 Vazquez et al. Eur.J. Phys. 2005

-3000 -2000 -1000 0 1000 2000 3000

-1.0

-0.5

0.0

0.5

1.0

M /

MS

Magnetic Field (Oe)

H paralelo

diámetro 35nm

VSM loop

LorTEM images in over- (a) and under-focused (b) conditions of an array Co NWs 45 nm in diameter and 55-nm long at remanence. The arrows show the transverse direction and the clockwise (red) and anticlockwise (blue) rotation of NW magnetization. As schematically shown on (c), the magnetic vortex acts as a convex or a concave lens, depending on its chirality, which creates a focus above or below the sample. Looking at these planes, we detect uniquely the presence of a vortex state and determine its chirality. On the hologram image (d) the high- and low-phase values are represented by two different color sequences that correspond to the clockwise and anticlockwise rotation of NW magnetization and (e) shows the contour lines corresponding to the B┴.

Lorentz microscopy & electron holography: Co nanowires

Electron holography directly measures the phase shift of the electron wave passing through the sample by measuring the phase shifts on the interferogram Ivanov et al.

(Submt. Sc. Reports)

Coercivity Hc as a function of NW diameter for single crystal hcp Co NWs

and different easy axis orientations (defined by the angle θ with NW axis)

Modeling: role of diameter & crystal symmetry

hcp Co nanowires (2 mm long) Changing the reversal mode with Anisotropy easy axis

Regions (1), (2), (3) correspond to applied fields at which a vortex is formed, at the remanence, and when the vortex core is switched

Uniform Alloy NW

Multisegmented in composition

Modulated in diameter

Individual FeCoCu Nanowires: artifially designed to control the reversal process

MFM image of uniform alloy Nanowire

Grown inside Hard-Mild pulsed anodized templates

Growing nanowires with modulated diameter (Co & CoFe)

Co nanowires

Fine control over shape of nanopores is hard to achieve

Diagram with two types of modulations

Kerr effect in individual modulated nanowires (Fe27Co68Cu5)

The presence of single and several Barkhausen jumps are detected depending on geometry

E. Palmero, C. Bran et al Nanotechnology (2015)

D1=150nm

D1=150nm, L1=800nm D2=170nm, L2= 50 nm

D1=130nm, L1=1000nm D2=100nm, L2= 300 nm

D1=150nm, L1=800nm D2=170nm, L2= 50 nm

Axi

al p

rofi

le o

f K

err

loo

ps

Angular dependence of Coercivity

Local MOKE loops along the nanowires

Fitting to vortex-like DW propagation mode

SEM images of modulated FeCoCu wires dispersed on Si substrate. FeCo modulated nanowires show bcc structure with a (110) orientation. Due to the small magnetocrystalline anisotropy, shape anisotropy, dominates Co nanowires show hcp structure with c-axis nearly perpendicular, magnetocrystalline anisotropy dominates

FeCoCu & Co modulated (bamboo-like) nanowires

FeCo MFM imaging: uniform vs. modulated nanowires

PEEM –XMCD results

XMCD contrast in a single FeCoCu modulated nanowire. - Direct photoemission (magnetic contrast from the top few nm, surface information) - Transmission data (shadow, x-rays partially transmitted through the wires, bulk information)

FeCoCu & Co bamboo-like modulated nanowires

XMCD images of CoFe and Co nanowires are recorded at the Fe and Co L3 and L2 edges reversing

the photon helicity using the PEEM end-station

Synchrotron Light Facility, Barcelona

Co nanowires Axial anisotropy Perpendicular anisotropy

Axial spins at the core

Vortex at the end

FeCoCu nanowires

PEEM –XMCD in bamboo-like modulated nanowires: information on surface and bulk spin configuration

MFM

MFM

Remanent spin configurations of (a) FeCoCu and (b) Co bamboo nanowires A half wire length is shown (1 micron) containing an edge and two modulations marked by the green arrows. Inserts show the transversal cross sections at the marked regions along the length: Black arrows denote the spin orientation in the corresponding section Red-White-Blue color contrast at background corresponds to axial magnetization.

J.A. Fdez-Roldán, mumag code

Simulations in CoFeCu and Co bamboo-like Nanowires at Remanence

Multisegmented nanowires: Structural data [FeCoCu/Cu]n

TEM images of FeCoCu(300 nm)/Cu(15 nm) nanowires: (a) Bright field image of an individual nanowire, (b) HRTEM image of a Cu spacer, (c) and d) Fast Fourier Transform at Cu and FeCoCu regions of the HRTEM image

Cu layers perfectly segregated from the FeCoCu; irregular and rough->the polycrystalline nature of the wires, the large grain size and inhomogeneities in the growth.

Proenca et al, Phys. Rev. B, 2013

Exchange coupling through oxidation of the inner walls

Core–Shell magnetic nanowires as new class of systems with composition and microstructure radial profile

.

Core/Shell nanowires & nanotubes at ICMM/CSIC

Ni –Polystere core/shell nanowires Alumina Membrane + PVA + Fe3O4 Mijangos et al, (I&EC research 2016)

Martin et al, J Nanosci.Nanotechn 2010

Magneto-polymeric hybrid systems

Fe/Fe3O4 core/shell nanowire

Growing of Nanotube and Core@Shell Nanowire Arrays

Nanotubes: Single Electrodeposition

Core@Shell: Double Electrodeposition

500 nm

Outer diameter ~ 300 nm Wall thickness ~ 30 nm Length ~ 15 mm 500 nm

FESEM

Controlled production of ordered arrays of Ni nanotubes

Outer diameter ~ 50 nm Wall thickness ~ 10 nm Length ~ 50 mm

50 nm diameter 10 nm wall thickness 50 mm length 105 nm intertube distance

Empty AAO membrane (a), Au nanotubes (b), TM@Au core/shell nanowires (c), contact removed TM@Au nanowires prepared for releasing (d).

Fe@Au core/shell nanowires: Au grown under different potentials: 0.35 (a), 0.8 (b), 1.0 (c) and 1.25V (d)

Two-step electrodeposition process to obtain core@shell nanowires

TM

Au

Cross-sectional

view of core-shell

Ovejero et al. (letter to JMMM)

From NW arrays to individual core@shell NWs

SEM images of Au nanotube arrays (a), and after filling with Fe (b), CoFe (c) and Ni (d). Fe@Au individual nanowires after released from the template (e).

Au Fe@Au

CoFe@Au Ni@Au

D. Magnin et al., Biomacromolecules 2008

Magneto-Biological functionalization: Nanowires vs. Nanoparticles ?

Non-chemotoxic induction of cancer cell death using magnetic NWs

Contreras et al, Int. J. Nanomedicine 2015

Osteosarcoma Cell Control with Ni/Au segmented nanowires

B.Stadler et al. Nanotechnology (2015)

CoPt/Au Multisegment Nanowires Functionalization for DNA detection

Ramulu et al. J. Electrochem. Sci. (2012)


2.- Magnetic Mcrowires:

FMR in biphase microwires

Controlled motion of single Domain-Wall in single phase microwires


Single and Bimagnetic Microwires: Preparation & Magnetics

An outer magnetic layer is grown by combined electroplating & sputtering

• Magnetic character is controlled by the choice of:

Alloys composition (soft/hard, hard/soft)

Internal/External phases thickness Magnetostatic Bias + Magnetoelastic Interaction

Nucleus (amorphous)

Shell (polycrystalline)

BI-MAGNETIC MICROWIRE

-40 -20 0 20 40-1,2

-0,6

0,0

0,6

1,2

1 mm CoNi

M (

x1

0-3

em

u)

H (kA/m)

Single CoFeSiB (Soft) CoFeSiB/NiFe (Soft/Soft) FeSiB/CoNi (Soft/Hard)

Network Analyser-FMR in microwires

The sample holder based on commercial SMA connectors provides reliable data up to 12 GHz

Simpler and more versatile technique than those based in µwires as part of the TL

DUT Irf

8 mm

Hdc

µwire Calibration: 50 Ω SMD resistor (electrical delay= 77 ps)

Collaboration V. Raposo (Un Salamanca)

Power Supply

Network Analyzer

SMA Cable

Helmholtz & Solenoid

Sample Holder

Computer control

Metallic diameter Dmet= 17 mm Total diameter D = (a) 42 mm, (b) 34 mm, (c) 20 mm

FMR CoFe-base single microwires: single absorption

Various Pyrex thickness

CoFeSiB non-magnetostrictive microwire, l ≈ -1x10-7

FMR CoFe-base biphase microwires: three absorption peaks

CoFeSiB soft non-magnetostrictive core, l ≈ -1x10-7

NiFe ultrasoft polycrystalline shell Metallic diameter Dmet= 17 mm Met. + Pyr. diameter D = (a) 42 mm, (b) 34 mm, (c) 20 mm NiFe thickness t= 2 mm


FMR CoFe-base biphase microwires: two absorption peaks


CoFeSiB non-magnetostrictive microwire, l ≈ -1x10-7

CoNi semi-hard polycrystalline shell Metallic diameter Dmet= 17 mm Met. + Pyr. diameter D = (a) 42 mm, (b) 34 mm, (c) 20 mm CoNi thickness t= 2 mm

CoNi shell was non magnetically saturated, is this the origin of the low f absorption?

Multiple absorption FMR in bimagnetic wires: summarizing

0 1 2 3 4 5 6 7 8 9 1040

80

120

160

200

240

280

R (

)

f (GHz)

4.9 kA/m

19.9 kA/m

35.1 kA/m

CoFe-FeNi (2-3 mm FeNi)

0,0 0,1 0,2 0,3 0,4 0,5 0,6

0

10

20

30

40

50f2

(G

Hz

2)

H (kOe)

FMR 1

FMR 2 (CoFe nucleus)

FMR 3 (FeNi shell)

CoFe glass-coated

linear fit

linear fit

4πMS= 11.5 kOe

4πMS= 6.9 kOe

??

• Soft/soft biphase system: CoFe/FeNi

• Soft/hard biphase system: CoFe/CoNi

FeNi shell was saturated, then a third absorption is observed

0 1 2 3 4 5-100

-50

0

50

100

150

200

R,X

(

)

f (GHz)

16 kA/m

R

X

??

Scheme of nucleation & depinning & propagation of a single Domain Wall (Magnetostrictive Fe rich microwires)

+ + - - - + +

+ +

+ + + - -

- -

- - + +

+ - - - -

- -

-

- +

-

- +

- -

+

+ + -

- -

+

+

+

-400 -200 0 200 400

-0,8

-0,4

0,0

0,4

0,8

M (

em

u)x

10

H (A/m)

Hsw ~ (1/m0MsVcr) { aEg+ bEsf}

DW

Reversal spontaneously begins at one end of the wire at a critical switching field


-Fluxmetric induction magnetometer (Home-designed),

based on Butta, Infante et al. Rev Sci Instrm 2009

For high sensitivity hysteresis loops and single DW dynamics

Magnetic Measurements

Voltage peaks induced at pick up coils as DW passes

t

Domain Wall velocity

Sixtus-Tonks like experiment

A single domain wall depins from one end

propagating along the entire wire

tdv /

1.55 1.60 1.65 1.70

-0.10

-0.05

0.00

0.05

0.10

dM/d

t (a.

u.)

t (ms)

v = S(H − H0)

be - eddy currents br - spin relaxation bs - structure relaxation

b reflects the interaction DW with defects

Single Domain Wall & Dynamics

Profiting of having a Single domain wall for fundamental dynamics studies

Damping mechanisms

DW motion equation

Exp. 1.-Trapping a Domain Wall: Sixtus & Tonks–like

- Homogeneous drive field, Hdr (solenoid) - Local field, HL - Two symmetric pick-up coils - Asymmetric positioning of the microwire: essential for the depinning of the standard wall, DWst, at the left wire’s end and its rigthward propagation

Under applied drive field by the solenoid, a reverse domain nucleates at the left wire’s end, and a “standard” wall depins and propagates along the wire

FeSiB microwire, 10 mm metallic diameter

Scheme of domain structure after a standard Domain Wall, DWst, moves under drive field, Hdr, plus “small-amplitude” antiparallel local field

Antiparallel local-field configuration: the Local field opposes the motion of DW by the Drive field

Braking and Trapping a Domain Wall

Braking &Trapping a domain wall: Antiparallel local-field configuration

DWst trapped at 4.27 mm to the left of the local coil

Experimental (blue) & calculated (red)

Pick up 1 Pick up 2

0,000 0,001 0,002 0,003 0,004-200

-100

0

100

200

320 360 400 440 480

0

2

4

6

H

(A/m

)

t (m s)

B

t (m s)

e.m

.f

(a.u

.)

Drive field Local field

HL>HLtrap

Drive, Hdr (blue) and Local, HL (green) fields and emf responses recorded in rigth (black) and left (red) sensing coils

HL < HLtrap

Velocity, v, of the standard wall, DWst, under drive field Hdr= 170 A/m, as a

function of the antiparallel local field, HL. The wall gets trapped at HL=610 A/m

Vázquez et al. Phys. Rev. Letters 108,037201 (2012)

Exp. 2.-Playing with the propagation of Single DW

The sequence of colored peaks confirms a Rightwards motion of the Single DW

for rightwards (bottom) and leftwards (upper)

applied field

Fe79Si10B8C3 microwire (dmet=20.5 mm, Dtot=30.5 mm)

- Multiple-coil system (2000 turns, 2 mm wide) - Extended length: 40 cm long wires - Square shaped 40 Hz field

A. Jimenez et al., Eur Phys J B 86, 113 (2013) invited JEMS 2012

microwire

S1 yellow

S2 blue

S3 pink

S4 green Pick-up coils Si

“Small” Applied Field, H = ± 213 A/m

H

H

“Medium” Applied Field = ± 262 A/m

H

S4 S3 S2 S1

DWst1 v

S4 S3 S2 S1

0H

S4 S3 S2 S1

DWst2

v

H

v

DWrev

Single DW rightwards motion (bottom) Two DWs moving in opposite directions (upper)

microwire

S1 yellow

S2 blue

S3 pink

S4 green

For Happ=-262 A/m, the signal at S4 (green) is received before the one in S3 (pink) denoting the presence of a second reverse wall, DWrev, propagating in the opposite direction

H

H

The appearance of a second DW moving opposite

“Large” Applied Field = ± 281 A/m

H

S4 S3 S2 S1

DWst1 v

S4 S3 S2 S1

0H

S4 S3 S2 S1

DWst2

v

H

v

DWrev

DWst2 and DWrev arrive to S3 simultaneously:

microwire

S1 yellow

S2 blue

S3 pink

S4 green

For Happ=-281 A/m, signals at S2 (blue) and S4 (green) are picked up simultaneously. Also, signal in S3 (pink) has higher amplitude and reduced width.

Observing the collapse of 2 single DWs moving in opposite directions

www.icmm.csic.es/gnmp/

Inst. Materials Science of Madrid

David Trabada Rafael P. del Real

Jose Miguel García Cristina Bran

Laura Vivas Rhimou ElKammouni

Ester Palmero

Oksana Chubykalo Yurii Ivanov Agustina Asenjo

Group of Nanomagnetism and Magnetization Processes

the scientific team in winter excursion by the mountains in Segovia looking for the roasted lamb Patones de Arriba,

Dec. 2015

2016.06.21 gmm csic NanoFrontMag

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