Magnetic Phase Transition and Exchange Bias in $$\hbox {Ni}_{45}\hbox {Co}_{5}\hbox {Mn}_{35.5}\hbox {In}_{14.5}$$ Ni 45 Co 5 Mn

Abstract

Magnetic properties and exchange bias of Ni 45 Co 5 Mn 35.5 In 14.5 ribbons were investigated by vibrating sample magnetometry (VSM) and electron magnetic resonance (EMR). Curie temperatures determined by using VSM and EMR methods are equal to 374 K and 377 K, respectively. Additionally, the EMR measurements revealed the existence of a weak ferromagnetic resonance (FMR) line in the paramagnetic region. The upward deviation of the integral intensity from Curie-Weis low below temperature T * and above T C confirms the existence of ferromagnetic phase in this temperature region. Below T C , the integral intensity does not saturate, which can suggest the coexistence of different magnetic phases at low temperature range. Additional confirmation on the coexistence of magnetic phases in the sample are asymmetric hysteresis loops associated with the spontaneous exchange bias effect. The dependence of EMR signal on cyclic repetition of measurement is also discussed.

Cobalt Content Effect on the Magnetic Properties of Ni50-xCoxMn35.5In14.5 Annealed Ribbons

“…The nature of the M(T) curves for annealed ribbons differs significantly from nonannealed ribbons [20][21][22]. The M(T) of the NC5MI sample displayed in Figure 2f is similar to magnetization of the ribbon before annealing [21].…”

“…The nature of the M(T) curves for annealed ribbons differs significantly from nonannealed ribbons [20][21][22]. The M(T) of the NC5MI sample displayed in Figure 2f is similar to magnetization of the ribbon before annealing [21]. This magnetization curve does not exhibit any thermal hysteresis and has a clear shift toward higher temperatures relative to non-annealed alloy [20,21].…”

“…This can lead to magnetic interactions of the FM and AFM type, which compete with each other at different temperatures, resulting in the observed magnetization. [20,21]. At the highest temperatures, the main line has an unchanged asymmetric character.…”

“…The difference in the value of Curie temperature obtained from VSM and EMR is a consequence of the different natures of both techniques. The EMR is sensitive to changes in the environment of the magnetic ions, so it is a good method for detecting local changes in properties of materials [21]. For conducting samples, due to an existing skin depth phenomenon, and the local character of the EMR method, one can notice a discrepancy between results determined from EMR data and VSM technique.…”

Large exchange bias in magnetic shape memory alloys by tuning magnetic ground state and magnetic-field history

“…Many investigations have demonstrated that the unidirectional anisotropy can be established below a blocking temperature during the FC process [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31]. On the other hand, in some Ni-Mnbased MSMAs, the unidirectional anisotropy can also be isothermally created by applying a sufficiently large H Max after a zero-field cooling (ZFC) process [32][33][34][35]. A magnetic field-induced transition even occurs from a super SG to a superferromagnetic domain state during the isothermal magnetization process, which leads to spontaneous EB behaviour [34,35].…”