Large perpendicular exchange bias and high blocking temperature in Al-doped Cr2O3/Co thin film systems

Tomohiro Nozaki; Yohei Shiokawa; Yukie Kitaoka; Yohei Kota; Hiroshi Imamura; Muftah Al-Mahdawi; Satya Prakash Pati; Shujun Ye; Syougo Yonemura; Tatsuo Shibata; Masashi Sahashi

doi:10.7567/apex.10.073003

Magnetic textures in hemispherical thin film caps with in-plane exchange bias

Journal of Applied Physics ◽

10.1063/5.0033772 ◽

2021 ◽

Vol 129 (1) ◽

pp. 015305

Author(s):

Andreea Tomita ◽

Meike Reginka ◽

Rico Huhnstock ◽

Maximilian Merkel ◽

Dennis Holzinger ◽

...

Keyword(s):

Thin Film ◽

Exchange Bias

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Magnetic properties of iron cluster/chromium matrix nanocomposites

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.6.117 ◽

2015 ◽

Vol 6 ◽

pp. 1158-1163 ◽

Cited By ~ 5

Author(s):

Arne Fischer ◽

Robert Kruk ◽

Di Wang ◽

Horst Hahn

Keyword(s):

Exchange Bias ◽

Cluster Size ◽

Complete Characterization ◽

Blocking Temperature ◽

Antiferromagnetic Coupling ◽

Magnetic Characteristics ◽

Iron Cluster ◽

The Matrix ◽

Cluster Distance ◽

Matrix Nanocomposites

A custom-designed apparatus was used for the fine-tuned co-deposition of preformed Fe clusters into antiferromagnetic Cr matrices. Three series of samples with precisely defined cluster sizes, with accuracy to a few atoms, and controlled concentrations were fabricated, followed by a complete characterization of structure and magnetic performance. Relevant magnetic characteristics, reflecting the ferromagnetic/antiferromagnetic coupling between Fe clusters and the Cr matrix, i.e., blocking temperature, coercivity field, and exchange bias were measured and their dependence on cluster size and cluster concentration in the matrix was analyzed. It is evident that the blocking temperatures are clearly affected by both the cluster size and their concentration in the Cr matrix. In contrast the coercivity shows hardly any dependence on size or inter-cluster distance. The exchange bias was found to be strongly sensitive to the cluster size but not to the inter-cluster distances. Therefore, it was concluded to be an effect that is purely localized at the interfaces.

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Microscopic model for exchange bias from grain-boundary disorder in a ferromagnet/antiferromagnet thin film with a nanocrystalline microstructure

Applied Physics Letters ◽

10.1063/1.4890580 ◽

2014 ◽

Vol 105 (3) ◽

pp. 032402 ◽

Cited By ~ 7

Author(s):

D. L. Cortie ◽

A. G. Biternas ◽

R. W. Chantrell ◽

X. L. Wang ◽

F. Klose

Keyword(s):

Thin Film ◽

Grain Boundary ◽

Exchange Bias ◽

Microscopic Model ◽

Nanocrystalline Microstructure

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Effect of ultra-thin Cu underlayer on the magnetic properties of Ni80Fe50 / Fe50Mn50 films

MRS Proceedings ◽

10.1557/proc-562-69 ◽

1999 ◽

Vol 562 ◽

Author(s):

C. Liu ◽

L. Shen ◽

H. Jiang ◽

D. Yang ◽

G. Wu ◽

...

Keyword(s):

Thin Film ◽

Atomic Force Microscopy ◽

Exchange Bias ◽

Film Material ◽

X Ray Diffraction ◽

X Ray ◽

Force Microscopy ◽

Atomic Force ◽

Maximum Value ◽

Film Roughness

ABSTRACTThe Ni80Fe20/Fe50Mn50,thin film system exhibits exchange bias behavior. Here a systematic study of the effect of atomic-scale thin film roughness on coercivity and exchange bias is presented. Cu (t) / Ta (100 Å) / Ni80Fe20 (100 Å) / Fe50Mno50 (200 Å) / Ta (200 Å) with variable thickness, t, of the Cu underlayer were DC sputtered on Si (100) substrates. The Cu underlayer defines the initial roughness that is transferred to the film material since the film grows conformal to the initial morphology. Atomic Force Microscopy and X-ray diffraction were used to study the morphology and texture of the films. Morphological characterization is then correlated with magnetometer measurements. Atomic Force Microscopy shows that the root mean square value of the film roughness exhibits a maximum of 2.5 Å at t = 2.4 Å. X-ray diffraction spectra show the films are polycrystalline with fcc (111) texture and the Fe50Mn50 (111) peak intensity decreases monotonically with increasing Cu thickness, t. Without a Cu underlayer, the values of the coercivity and loop shift are, Hc = 12 Oe and Hp = 56 Oe, respectively. Both the coercivity and loop shift change with Cu underlayer thickness. The coercivity reaches a maximum value of Hc= 36 Oe at t = 4 Å. The loop shift exhibits an initial increase with t, reaches a maximum value of HP = 107 Oe at t = 2.4 Å, followed by a decrease with greater Cu thickness. These results show that a tiny increase in the film roughness has a huge effect on the exchange bias magnitude.

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Giant exchange bias effect in all-3d-metal Ni38.8Co2.9Mn37.9Ti20.4 thin film

Applied Physics Letters ◽

10.1063/1.5129878 ◽

2020 ◽

Vol 116 (2) ◽

pp. 022412

Author(s):

K. Liu ◽

S. C. Ma ◽

Z. S. Zhang ◽

X. W. Zhao ◽

B. Yang ◽

...

Keyword(s):

Thin Film ◽

Exchange Bias ◽

Bias Effect ◽

Exchange Bias Effect

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Magnetic properties of epitaxial TmFe2O4 thin films with an anomalous interfacial structure

Journal of Materials Chemistry C ◽

10.1039/d0tc01367f ◽

2020 ◽

Vol 8 (34) ◽

pp. 11704-11714

Author(s):

You Jin Kim ◽

Shinya Konishi ◽

Yuichiro Hayasaka ◽

Ryo Ota ◽

Ryosuke Tomozawa ◽

...

Keyword(s):

Thin Film ◽

Magnetic Properties ◽

Exchange Bias ◽

Interface Structure ◽

Yttria Stabilized Zirconia ◽

Interfacial Structure ◽

Stabilized Zirconia ◽

Bias Effect ◽

Exchange Bias Effect ◽

Glassy Behavior

Epitaxial TmFe2O4 thin film with self-assembled interface structure was grown on yttria-stabilized zirconia substrate. TmFe2O4 phase itself shows glassy behavior and the interface leads to the exchange bias effect.

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Bulk-like dielectric and magnetic properties of sub 100 nm thick single crystal Cr2O3 films on an epitaxial oxide electrode

Scientific Reports ◽

10.1038/s41598-020-71619-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

N. M. Vu ◽

X. Luo ◽

S. Novakov ◽

W. Jin ◽

J. Nordlander ◽

...

Keyword(s):

Thin Film ◽

Magnetic Properties ◽

Single Crystal ◽

Dielectric Breakdown ◽

Second Harmonic ◽

Blocking Temperature ◽

Antiferromagnetic Order ◽

Low Dielectric ◽

Crystal Films ◽

Thin Film Electrodes

Abstract The manipulation of antiferromagnetic order in magnetoelectric Cr2O3 using electric field has been of great interest due to its potential in low-power electronics. The substantial leakage and low dielectric breakdown observed in twinned Cr2O3 thin films, however, hinders its development in energy efficient spintronics. To compensate, large film thicknesses (250 nm or greater) have been employed at the expense of device scalability. Recently, epitaxial V2O3 thin film electrodes have been used to eliminate twin boundaries and significantly reduce the leakage of 300 nm thick single crystal films. Here we report the electrical endurance and magnetic properties of thin (less than 100 nm) single crystal Cr2O3 films on epitaxial V2O3 buffered Al2O3 (0001) single crystal substrates. The growth of Cr2O3 on isostructural V2O3 thin film electrodes helps eliminate the existence of twin domains in Cr2O3 films, therefore significantly reducing leakage current and increasing dielectric breakdown. 60 nm thick Cr2O3 films show bulk-like resistivity (~ 1012 Ω cm) with a breakdown voltage in the range of 150–300 MV/m. Exchange bias measurements of 30 nm thick Cr2O3 display a blocking temperature of ~ 285 K while room temperature optical second harmonic generation measurements possess the symmetry consistent with bulk magnetic order.

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