Relating field-induced shift in transition temperature to the kinetics of coexisting phases in magnetic shape memory alloys

Abstract

In a magnetic shape memory alloy system, we vary composition following phenomenological arguments to tune macroscopic properties. We achieve significantly higher shift in austenite to martensitic phase transition temperature with magnetic field. This enhancement is accompanied by significant broadening of the transition and by field-induced arrest of kinetics, both of which are related to the dynamics of the coexisting phases. This reveals hitherto unknown interrelationship between different length-scales. This may serve as an effective route for comprehensive understanding of similar multicomponent systems which show considerable variation in physical properties by minor change in microscopic parameters.

First-order antiferro–ferromagnetic transition in Fe49(Rh0.93Pd0.07)51under simultaneous application of magnetic field and external pressure

“…Similar behavior has been observed in many other systems i.e. sharp transition during warming compared to that observed during cooling [21,22,28,38]. To study, if this difference is due to lower T* compared to T**, we have chosen a set of H and P values such that T*(H1, P1) = T**(H2, P2).…”

Structural and magnetic properties probed using neutron diffraction technique in Ni50−xCoxMn38Sb12 (x=0 and 5) Heusler system

“…The key to these striking properties is the strong coupling between structural and magnetic degrees of freedom. This coupling gives rise to the martensitic transition which is a first order magneto-structural transition that occurs from the high temperature austenite (cubic) phase to the low temperature martensite (orthorhombic or tetragonal) phase [12,13]. Magnetic properties in these two states are mainly contributed by the Mn sublattice, as Ni atoms possess a very small moment in these alloys [14].…”

Interrupted Magnetic First Order Transitions and Kinetic Arrest probed with In-field Neutron Diffraction

“…While in some cases the magnetic FOPT could be of the order-order type, driven by change of magnetic exchange interactions, it could also be accompanied by changes in volume or the symmetry of the crystal lattice. It is well-known that due to the presence of quenched disorder, there is a broadening of the FOPT which results in a distribution of transition temperatures [1][2][3][4][5][6][7][8]. Though temperature is the most commonly used thermodynamic variable for observing FOPT, pressure, magnetic and electric fields could also be useful second thermodynamic variables.…”

“…Though temperature is the most commonly used thermodynamic variable for observing FOPT, pressure, magnetic and electric fields could also be useful second thermodynamic variables. It is possible to interrupt the FOPT by using an effective combination of these two variables, resulting in phase coexistence of magnetically ordered metastable states and equilibrium phases, collectively called kinetically arrested state or magnetic glass [1][2][3][4][5][6]. In such a state, the phase coexistence would persist down to the lowest temperature.…”