Probing the electronic structure of Ni–Mn–In–Si based Heusler alloys thin films using magneto-optical spectra in martensitic and austenitic phases

Abstract

Thin films of Ni 52 Mn 35-x In 11+x Si 2 were fabricated by magnetron sputtering on MgO (001) single crystal substrates. Magnetization as function of temperature for Ni 52 Mn 35 In 11 Si 2 exhibits features consistent with a magnetostructural transition (MST) from an austenitic phase to a martensitic phase, similar to the bulk material. We observed that the martensitic transformation is externally sensitive to small changes in chemical composition and stoichiometry. It has been found that thin films of Ni 52 Mn 34-x In 11+x Si 2 with x=0 and 1 undergo a temperature-induced MST or remain in a stable austenitic phase, respectively. Comparison of magneto-optical transverse Kerr effect spectra obtained at 0.5-4.0 eV in the 35-300 K temperature interval reveal insignificant differences between the martensitic and austenite phases. We found that the field and temperature dependencies of the transverse Kerr effect are quite different from the magnetization behavior, which is attributed to magnetic inhomogeneity across the films. To elucidate the effects of magnetostructural phase transitions on the electronic properties, we performed density functional calculations of the magneto-optical Kerr effect.

Magneto-Optical Study of Martensitic Transition in Ni₄₅Mn_36.7In_13.3Co₅(at. %) Single Crystals

“…It is interesting to compare the MO spectra for the studied Ni 45 Mn 36.7 In 13.3 Co 5 samples and data available in literature. MO spectra profile of Ni 45 Mn 36.7 In 13.3 Co 5 single crystals is similar but not identical with that for Ni 50 Mn 35 In 15 thin films [7] and Ni 47 Mn 41 In 12 ribbons [8]. Differences of presented spectra for Ni 2 MnIn thin films are more substantial [9].…”

“…In the present work, we applied MO technique in the geometry of TKE in the light energy range of 0.5 -4.0 eV to study MO spectra of l martensitic and austenitic states of Ni 45 Mn 36. 7 In 13. 3 Co 5 (at.%) single crystals.…”

Effect of Crystalline Structure on Some Physical Properties of Bulk and Thin Film Ni$_{50}$Mn$_{35}$In$_{15}$ Alloy Samples

“…В роботі [23] було проведено теоретичний розрахунок спектрів ОП сплавів Ni 3 Mn 1−x Al x (x = 0,00; 0,25; 0,50 та 0,75) і показано, що зміна складу сплаву залишає незмінним спектр ОП з двома смугами поглинання, впливаючи лише на незначний їх зсув по енергії. Подібний результат був також одержаний для теоретично обрахованих спектрів екваторіального ефекту Керра (ЕЕК) і показано, що зміна складу сплавів Ni 8 Mn X In Y (X = 4, 5, 6; Y = 2, 3, 4) викликає зсув по енергії максимумів поглинання, залишаючи практично незмінною саму двосмугову форму спектрів ЕЕК [24]. На підставі цього можна, мабуть, припустити, що і в нашому випадку нестехіометричні масивні та плівкові зразки сплавів Ni-Mn-In мають подібну до стехіометричного сплаву Ni 2 MnIn природу смуг міжзонного поглинання.…”

Visualization of magnetostructural transition in Heusler alloys by Magnetic Force Microscopy

“…Typically, Heusler alloys are studied in bulk form by SQUID magnetometry [4], optical magnetic methods [5], calorimetry [5], volumetry [6] and standard structural approaches such as XRD [7]. However, neither of the abovementioned methods can reveal micro-and nanoscale details of a mechanism of magnetostructural transition.…”