Investigation of the inverse magnetocaloric effect with the fraction method

Abstract

In this study, we examine Ni49Nb1Mn36In14 (nom. at.%) magnetic shape memory alloy (MSMA) to illustrate the inverse magnetocaloric effect using the fraction method. The magnetic entropy change, ∆S_mag, was calculated with both, the fraction method and the thermomagnetic Maxwell relation. Our results demonstrate that there exists a large magnetization difference between field-cooling and field-heating histories in Ni49Nb1Mn36In14 (nom. at.%) MSMA, which can be attributed to the pinning of lattice entropy and magnetic entropy, as it is well-known that the temperature and applied magnetic fields have an opposing effect on the total entropy change. In addition, we describe the inverse magnetocaloric effect and the contradictory roles on the total entropy change between the two stimuli via the fraction method.

Tuning of the magneto-caloric effects in Ni43Mn46In11 magnetic shape memory alloys by substitution of boron

“…We numerically estimated the magnetic field-induced entropy change (∆S) around magnetic transition using the relationship ∆S In 11 alloy, the transition entropy was calculated as 18.2 J kg −1 K −1 from DSC data, and the magnetic field-induced entropy change for demagnetization was calculated as 8.19 J kg −1 K −1 which shows that during magnetic field induced transition smaller fraction of the Ni 43 Mn 45.3 B 0.7 In 11 alloy transforms reversibly with respect to Ni 43 Mn 45.0 B 1.0 In 11 alloy. Therefore, it was reported that by using fractional method on MSMAs the lesser counteract of lattice entropy and magnetic entropy to each other, one can observe higher inverse MCE values which is valid for this study [25]. From the standpoint of the MCE's reversibility, which is connected to the transition's hysteresis and the sensitivity of the transition temperatures to the applied magnetic field (dA f /dH).…”

“…The existence of spin glass peak was explained to be due to the result of mixed magnetic interactions between ferromagnetic and antiferromagnetic clusters [50,51]. Among the other things, there exist a hysteresis between FC and FH curves for all applied magnetic fields which is quite evident for 100 Oe measurement reported in our previous studies [25,52]. Moreover, it is reported that antiferromagnetic exchange leading to local noncollinear spin structures, which can pin the ferromagnetic domains in different configurations [53].…”

“…These materials' physical properties are significantly affected by their chemical composition, enabling the coupling of the second-order magnetic transition with the first-order structural change, thereby amplifying the MCE [23]. In addition, the competition of structural and magnetic entropy change contributions was reported in recent studies where lattice entropy is dominating and magnetic entropy is non-synergetic with it, ultimately revealing the dilemma of inverse magnetocaloric materials [24,25].…”

Crystal Structure and Properties of Heusler Alloys: A Comprehensive Review

“…Therefore, the entropy variation as a function of temperature for the highest applied magnetic field (5 T) was 15 J/K/kg for x = 0.15 and 18 J/K/kg for x = 0.13. Furthermore, other Heusler alloys exhibit the inverse magnetocaloric effect such as Ni-Mn-In-X [87] and Ni-Mn-Sn-X [88].…”

Investigation of the effect of martensitic phase transition temperature and Curie temperature difference on magnetic and magnetocaloric properties under low magnetic field on Si-doped Ni-Mn-In Heusler alloys

“…Furthermore, it has been demonstrated that in NiMnIn MSMAs, the magnetic field-induced decrease in martensitic transformation temperatures is closely correlated with the temperature differential between the high-temperature austenite phase's Curie point (T C ) and the mean martensitic transformation temperature (T M ). In such instances, elevated values of(T M -T C ) are typically associated with a more pronounced magnetic field-induced transformation temperature shift [26][27][28]. Since the change of long-range atomic order has a dual impact on both the martensitic transition and the magnetic properties.…”