Interfacial Ferromagnetic Coupling and Positive Spontaneous Exchange Bias in SrFeO_3–x/La_0.7Sr_0.3MnO₃ Bilayers

Abstract

Negative exchange bias is usually discovered in ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures after a field-cooling (FC) process. Relatively, positive exchange bias (PEB) is a rarely observed phenomenon. So far, almost all of the models for PEB whether undergoing FC or zero-field-cooling (ZFC) treatment have been explained by an interaction of strong AFM coupling at the interface. In this work, by selecting a special material of SrFeO3–x as the AFM layer, coupled with FM-La0.7Sr0.3MnO3 (LSMO), we obtain a novel PEB effect of the bilayer after ZFC measurement, of which the shift directions are unfixable and dependent on the initial magnetization direction. Based on a transient magnetic field to control the remanence (M r) direction of LSMO at room temperature and then cooling below the T N of SrFeO3–x without any magnetic field disturbance, the shift direction can be locked only toward the transient magnetic field. Combined with experimental results and first-principles calculations, we propose that the above phenomena are explained as the field-induced AFM phase of SrFeO3–x transforming into the FM phase at an FM coupling bilayer interface. Thus, our finding may provide a new approach to realize and tune the zero-field-cooling PEB with FM coupling heterostructures.

Tuning the Exchange Bias Effect in 2D van der Waals Ferro‐/Antiferromagnetic Fe3GeTe2/CrOCl Heterostructures

“…Besides, since the thickness of antiferromagnet (t AFM ) is also a crucial parameter for J AFM-FM , t AFM may affect the magnitude of H EB as well. [43] When the FGT thickness is fixed at 27 nm, the H EB slightly increases from +148.3 Oe (−100.3 Oe) to +241.4 Oe (−201.7 Oe) under NFC (PFC) with the decrease of t AFM from 28 nm (Figure 2b) to 10 nm (Figure 4a), and similar results have also been observed in the FGT/CrCl 3 heterostructure. [25] The cooling field is another important factor in determining the H EB .…”

Bending strain tailored exchange bias in epitaxial NiMn/ γ ′-Fe4N bilayers

“…S5 of the supplementary material). 3,36 Figures 2(a Meanwhile, at t ¼ 8 nm, H C also reaches the maximum value of 328 Oe, which is much larger than H C of c 0 -Fe 4 N single layer with the same thickness. 37 Generally, EB is induced by the exchange coupling at the FM/AFM interfaces, where the exchange coupling can affect the magnetization reversal of the FM layer by pinning effects.…”

“…Flexible spintronic devices are important for practical applications in the fields of information, medical care, and energy due to the advantages of flexibility, wearability, low cost, etc. 1,2 It is critical to fabricate functional magnetic films onto flexible substrates for the desired flexible spintronic devices, such as exchange biased heterostructures 3,4 and giant magnetoresistance multilayers. 5 Exchange bias (EB) is also one of the key factors in determining the performances of flexible spintronic devices, which have been used in magnetic random access memories and magnetoresistive read heads.…”

Zero-field cooling exchange bias induced by spin metastable state in MnNiGa system

“…研究者 相继在Ni 2 Mn 1.4 Ga 0.6 [14] , Ni 50 Mn 36 Co 4 Sn 10 [15] , Ni 50 Mn 50−x -Sn x [16] , Ni 50 Mn 38 Ga 12−x Sb x [17] , Mn 50 Ni 40 Sn 10−x Si x [18] , Mn 50 -Ni 50−x Al x [19] , Ni 50 Mn 34 In 13 Fe 3 [20] 等Heusler合金体系, PdNCr 3 [21] , Mn 3 Co 1−x Mn x N [22,23] 等反钙钛矿氮化物体系, 以及La 1.5 Sr 0.5 CoMnO 6 [24] , Pr 1-x Ca x MnO 3 [25] , YMnO 3 [26] , Y 0.9 Pr 0.1 CrO 3 [27] , Co 0.8 Cu 0.2 Cr 2 O 4 [28] , La 2−x A x CoMnO 6−δ (A = Ba, Ca, Sr; x = 0, 0.5) [29] 等钙钛矿、尖晶石氧化 物体系中观测到ZEB. 最近, Zhang等人 [30] 在La 0.7 Sr 0.3 - [31] . 所以在富Mn的偏分Heusler化合物中, Mn原 子占据多套磁性子晶格, 表现出丰富的磁结构和磁学 性质 [32,33] .…”