Multiple ferroic glasses via ordering

Abstract

Structural glasses are characterized by the loss of long-range translational and rotational symmetry. In the last two decades, however, it has been discovered that materials that exhibit ferroic (ferromagnetic, ferroelectric and ferroelastic) phase transformations may also exhibit glassy behavior, in which the ferroic degrees of freedom (magnetization, polarization, strain) exhibit a loss of long-range translational symmetry. A consequence of this loss of longrange symmetry is the suppression of the ferroic phase transitions. Moreover, these unique glassy systems exhibit dynamic and thermodynamic behavior analogous to regular structural glasses.Conventionally, the onset of glassy behavior is brought about by the introduction of spatial heterogeneities, typically originating from point defects, particularly in the case of strain glasses.Here, we demonstrate, for the first time, that configurational order/disorder in a single ferromagnetic alloy (Ni 45 Co 5 Mn 36.6 In 13.4 ) can be used to stabilize both strain and magnetic glasses. The control of the degree of configurational order--through simple heat treatment schedules--, and simultaneous application of stress and magnetic field enabled us to observe a Kauzmman point, that is, the collapse of the entropy difference between a crystalline and a glassy phase. Systematic investigation of the transformation behavior in this system as a function of heat treatment enabled us to observe four kinds of solid-solid phase transitions (ferromagnetic-paramagnetic, martensitic transformation, strain and magnetic glass) in a single composition. The alloy investigated can be used to further elucidate the nature of ferroic glass transitions and their coupling.

Reversible Martensitic Transformation under Low Magnetic Fields in Magnetic Shape Memory Alloys

“…Varying the degree of long-range order in these materials can be used to tune their magnetocaloric operating temperatures, i.e. the martensitic transformation temperatures and characteristics33343536. In turn, these characteristics influence the magnetic field levels needed to completely transform the alloy, which has been shown to influence the degree of achievable magnetocaloric cooling3738394041.…”

“…Our intent was to grow a B2 order-dominant microstructure3436. Secondary annealing below the reported L2 1 to B2 ordering temperature (900 K)35 was also performed on some single crystal compression samples.…”

The metamagnetic behavior and giant inverse magnetocaloric effect in Ni–Co–Mn–(Ga, In, Sn) Heusler alloys

“…In particular magnetic Heusler alloys with martensitic phase transition may show cluster-spin glass features due to enhanced magnetic frustration in martensite and chemical disorder as has actually been observed in Ni-Co-Mn-(In, Sn) [8,19,20]. In particular, it has been argued that kinetically arrested first-order transition may give rise to strain-glass non-equilibrium phenomena.…”

Atomic order and martensitic transformation entropy change in Ni–Co–Mn–In metamagnetic shape memory alloys

“…As a result, the thermal MT is completely arrested [24][25][26] and the critical stress or magnetic field to induce the transformation becomes independent of temperature [23,19]. At temperatures below the arrested transformation, DS mag may even exceed in magnitude the vibrational term, DS vib , and produce an anomalous change of sign of the total DS tr [12,27,28].…”