Spontaneous exchange bias: Unidirectional anisotropy in an otherwise isotropic system

2007 ◽  
Vol 76 (10) ◽  
Author(s):  
Jyotirmoy Saha ◽  
R. H. Victora
Keyword(s):  
Exchange Bias ◽  
Isotropic System ◽  
Unidirectional Anisotropy

Exchange Bias in Co/FeMn and Co/IrMn Structures Induced by Deposition in Presence of Magnetic Field

2012 ◽  
Vol 190 ◽  
pp. 93-96
Author(s):  
I.O. Dzhun ◽  
N.G. Chechenin ◽  
S.A. Dushenko ◽  
E.A. Konstantinova
Keyword(s):  
Magnetic Field ◽  
Angular Dependence ◽  
Exchange Bias ◽  
Low Temperatures ◽  
Resonance Field ◽  
Blocking Temperature ◽  
Bilayer Structure ◽  
Magnetron Deposition ◽  
Unidirectional Anisotropy ◽  
Antiferromagnetic Layer

By measuring the angular dependence of ferromagnetic resonance field at room and low temperatures, it is demonstrated that the magnitude of magnetic field applied during magnetron deposition of Ta/F/AF/Ta structures, where F=Co, NiFe and AF=FeMn and IrMn, influences the uniaxial and unidirectional anisotropy, magnetization and the exchange bias blocking temperature. The deposition field effects on the bilayer structure are compared with the effects on a similar structure, but without antiferromagnetic layer. The exchange bias blocking temperature of investigated structures is found to be significantly lower than the Néel temperature of a bulk antiferromagnet. The origin of the observed effects is shortly discussed.

Observation of giant exchange bias effect in Ni-Mn-Ti all-d-metal Heusler alloy

2021 ◽  
Author(s):  
Saheli Samanta ◽  
Subrata Ghosh ◽  
Kalyan Mandal
Keyword(s):  
Exchange Bias ◽  
Heusler Alloy ◽  
Magnetic Relaxation ◽  
Training Effect ◽  
Magnetic Memory ◽  
Relaxation Processes ◽  
Bias Effect ◽  
Exchange Bias Effect ◽  
Intrinsic Nature ◽  
Unidirectional Anisotropy

Abstract We report a giant exchange bias (EB) field of about 3.68 KOe during field cooled process in all-d-metal Ni40(FeCo)4Mn36Ti20 Heusler alloy. The study of magnetic memory effect and isothermal magnetic relaxation processes suggest that the giant EB field arises due to the possible coexistence of antiferromagnetic (AFM) and ferromagnetic (FM) phase exchange interaction in the studied system at temperatures below 35 K. Furthermore, the temperature and cooling field dependence of EB effect are analyzed which are related to the change in unidirectional anisotropy at FM/AFM interface. The study of a well-established training effect confirms the intrinsic nature of the observed EB behavior. This result will open up a new way towards the development of EB materials considering all-d-metal Heusler alloy systems.

scholarly journals Voltage control of unidirectional anisotropy in ferromagnet-multiferroic system

2018 ◽  
Vol 4 (11) ◽  
pp. eaat4229 ◽  
Author(s):  
Sasikanth Manipatruni ◽  
Dmitri E. Nikonov ◽  
Chia-Ching Lin ◽  
Bhagwati Prasad ◽  
Yen-Lin Huang ◽  
...  
Keyword(s):  
Electric Field ◽  
Exchange Bias ◽  
Room Temperature ◽  
Uniaxial Anisotropy ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
State Variables ◽  
Ultralow Energy ◽  
Unidirectional Anisotropy ◽  
Beyond Cmos

Demonstration of ultralow energy switching mechanisms is imperative for continued improvements in computing devices. Ferroelectric (FE) and multiferroic (MF) order and their manipulation promise an ideal combination of state variables to reach attojoule range for logic and memory (i.e., ~30× lower switching energy than nanoelectronics). In BiFeO3(BFO), the coupling between the antiferromagnetic (AFM) and FE order is robust at room temperature, scalable in voltage, stabilized by the FE order, and can be integrated into a fabrication process for a beyond-CMOS (complementary metal-oxide semiconductor) era. The presence of the AFM order and a canted magnetic moment in this system causes exchange interaction with a ferromagnet such as Co0.9Fe0.1or La0.7Sr0.3MnO3. Previous research has shown that exchange coupling (uniaxial anisotropy) can be controlled with an electric field. However, voltage modulation of unidirectional anisotropy, which is preferred for logic and memory technologies, has not yet been demonstrated. Here, we present evidence for electric field control of exchange bias of laterally scaled spin valves that is exchange coupled to BFO at room temperature. We show that the exchange bias in this bilayer is robust, electrically controlled, and reversible. We anticipate that magnetoelectricity at these scaled dimensions provides a powerful pathway for computing beyond modern nanoelectronics by enabling a new class of nonvolatile, ultralow energy computing elements.

Exchange bias on rippled substrates ¢?? step induced uniaxial versus unidirectional anisotropy

2006 ◽  
Author(s):  
M. Liedke ◽  
S. Rossbach ◽  
S. Facsko ◽  
B. Hillebrands ◽  
J. Fassbender
Keyword(s):  
Exchange Bias ◽  
Unidirectional Anisotropy

Exchange bias and anomalous vertical shift of the hysteresis loops in milled Fe/MnO2 material

2006 ◽  
Vol 299 (1) ◽  
pp. 11-20 ◽  
Author(s):  
E.C. Passamani ◽  
C. Larica ◽  
C. Marques ◽  
J.R. Proveti ◽  
A.Y. Takeuchi ◽  
...  
Keyword(s):  
Exchange Bias ◽  
Hysteresis Loops ◽  
Vertical Shift
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