Effects of surface topology and texture on exchange anisotropy in NiFe/Cu/NiFe/FeMn spin valves

Park, C.‐M.; Min, Kyeong-Ik; Shin, Kyung-Hun

doi:10.1063/1.361891

Cited by 49 publications

(17 citation statements)

References 4 publications

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“…[293]) and H e and T B are sizedependent, which is emphasized in this section. Besides, H e and T B are also functions of AFM orientation (compensated versus uncompensated AFM surface [298][299][300][301][302][303] and in-plane versus out-of-plane AFM spins [298,299,302]), of FM/AFM interface disorder (roughness [299,301,302,[304][305][306], crystallinity [307,308], grain size [309,310], of interface impurity layers [311]), and of strain effect [312][313][314], of stoichiometry [293] or of presence of multiple phases [315] and so forth.…”

Section: Exchange Bias In Fm/afm Heterostruc-turesmentioning

confidence: 99%

Size Dependence of Structures and Properties of Magnetic Materials

Jiang¹,

Lang²

2007

TONANOJ

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Due to the involvement of high portion of atomic coordination imperfection in surfaces and interfaces, the properties of magnetic nanocrystals dramatically differ from that of the corresponding bulk counterparts, which have led to a surge in both experimental and theoretical investigations in the past decades. This review summarizes the studies for these size-dependent magnetic properties, and additional thermal or phase stabilities, and mechanical properties. To interpret the above phenomena, a thermodynamic model for the size dependence and interface dependences of these properties is described, which is based on Lindemann s criterion for melting, Mott s expression for the vibrational melting entropy, and Shi s model for the size-dependent melting temperature. The model without any adjustable parameter is confirmed by a large number of experimental results, and helps us to understand the structures and properties of the magnetic nanocrystals. Moreover, other theoretical works on the above properties are also mentioned and commented.

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Section: Exchange Bias In Fm/afm Heterostruc-turesmentioning

confidence: 99%

Size Dependence of Structures and Properties of Magnetic Materials

Jiang¹,

Lang²

2007

TONANOJ

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“…Exchange coupling between FeMn and NiFe (permalloy, Py) layers is widely used to fabricate spin valve MR devices [1,2]. Py has been used as a seed layer for FeMn and also used as pinned layer [3].…”

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confidence: 99%

Asymmetric exchange bias in NiFe/FeMn/NiFe multilayer films

Lee¹,

Hong²,

Kim³

et al. 2004

Journal of Magnetism and Magnetic Materials

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“…A complete description of exchange anisotropy would incorporate an explanation of the mechanism for exchange biasing [2][3][4][5][6][7][8], the effects of interface disorder [9][10][11], the relationship between the exchange bias ͑H E ͒ and the coercivity ͑H C ͒ [6,12,13], as well as an understanding of the magnetization reversal mechanisms [14][15][16]. In an attempt to address these issues, we have focused on a model thin film system TMF 2 ͞Fe (TM transition metal), with which we have been able to elucidate perpendicular coupling [17], effects of compensation [18] and interfacial disorder [9,10], and the relationship between H E and H C [12].…”

mentioning

confidence: 99%

Two-Stage Magnetization Reversal in Exchange Biased Bilayers

et al. 2001

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MnF 2 ͞Fe bilayers exhibit asymmetric magnetization reversal that occurs by coherent rotation on one side of the loop and by nucleation and propagation of domain walls on the other side of the loop. Here, we show by polarized neutron reflectometry, magnetization, and magnetotransport measurements that for samples with good crystalline "quality" the rotation is a two-stage process, due to coherent rotation to a stable state perpendicular to the cooling field direction. The result is remarkably asymmetrically shaped hysteresis loops. DOI: 10.1103/PhysRevLett.86.4394 PACS numbers: 75.70.Cn, 75.30.Gw Despite recently renewed interest in the phenomenon of exchange anisotropy [1] at the interface between antiferromagnets (AF) and ferromagnets (F), a full understanding is elusive [2]. A complete description of exchange anisotropy would incorporate an explanation of the mechanism for exchange biasing [2][3][4][5][6][7][8], the effects of interface disorder [9][10][11], the relationship between the exchange bias ͑H E ͒ and the coercivity ͑H C ͒ [6,12,13], as well as an understanding of the magnetization reversal mechanisms [14][15][16]. In an attempt to address these issues, we have focused on a model thin film system TMF 2 ͞Fe (TM transition metal), with which we have been able to elucidate perpendicular coupling [17], effects of compensation [18] and interfacial disorder [9,10], and the relationship between H E and H C [12].A recent thrust has been to understand the mechanisms by which the magnetization reverses in such systems [15]. This is a fundamental point, clearly related to the behavior of H C (zero moment half-width of the hysteresis loop), which is considered important [6]. Although there are few more fundamental questions about the nature of a hysteresis loop than the issue of the magnetization reversal mechanism, it has largely escaped investigation in exchange biased systems. Recent papers [14,15] have contributed to the realization that the magnetization reversal is intrinsically asymmetric under certain conditions. This naturally explains the often observed [1,[18][19][20] [22]. In summary, it is clear that reversal asymmetry in exchange biased systems is a general phenomenon requiring immediate attention.In the MnF 2 ͞Fe and FeF 2 ͞Fe systems, we have shown that for certain cooling field orientations the magnetization reverses by coherent rotation on the high field side of the loop (i.e., where the coercive field is jH E j 1 H C ) and by domain wall nucleation and propagation on the low field side of the loop (i.e., where the coercive field is H C 2 jH E j), a very clear asymmetry [15]. The magnetization hysteresis loops show very slight shape asymmetry, which must be associated with this effect [23]. The asymmetry is easily understood on consideration of the twinned nature of the AF films (Fig. 1). When the cooling field bisects the twin anisotropy axes (as shown), the frustration of the coupling between the individual AF twins and the ferromagnetic overlayer leads to an effective "45 ± coupling," r...

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Effects of surface topology and texture on exchange anisotropy in NiFe/Cu/NiFe/FeMn spin valves

Cited by 49 publications

References 4 publications

Size Dependence of Structures and Properties of Magnetic Materials

Size Dependence of Structures and Properties of Magnetic Materials

Asymmetric exchange bias in NiFe/FeMn/NiFe multilayer films

Two-Stage Magnetization Reversal in Exchange Biased Bilayers

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