Structural, electrical and magnetic properties of nanostructured Mn2Ni1.6Sn0.4 melt spun ribbons

TL;DR

This study investigates the nanostructured Mn2Ni1.6Sn0.4 ribbons, revealing phase transitions, magnetic behaviors, and the presence of a canonical spin glass state due to nanostructuring effects.

Contribution

It provides new insights into the magnetic and structural properties of nanostructured Mn2Ni1.6Sn0.4, highlighting the coexistence of phase transitions and spin glass behavior in melt-spun ribbons.

Findings

Identified austenite-martensite phase transition around 240-260 K.

Confirmed the existence of a canonical spin glass below 145 K.

Observed hysteresis in magnetization and resistivity indicating first-order phase transition.

Abstract

Nanocrystalline ribbons of inverse Heusler alloy Mn2Ni1.6Sn0.4 have been synthesised by melt spinning of the arc melted bulk precursor. The single phase ribbons crystallize into a cubic structure and exhibit very fine crystallite size of < 2 nm. Temperature dependent magnetization (M-T) measurements reveal that austenite (A)-martensite (M) phase transition begins at T~248 K and finishes at T~238 K during cooling cycle and these values increase to T~267 K and T~259 K while warming. In cooling cycle, the A-phase shows ferromagnetic (FM) ordering with a Curie temperature T~267 K, while both the FM-antiferromagnetic (AFM) and M-transitions occur at T~242 K. The M-phase undergoes FM transition at T~145 K. These transitions are also confirmed by temperature dependent resistivity measurements. The observed hysteretic behaviour of magnetization and resistivity in the temperature regime spanned by the A-M transition is a manifestation of the first order phase transition. Magnetization and susceptibility data also provide unambiguous evidence in favour of spin glass . The scaling of the glass freezing temperature (Tf) with frequency, extracted from the frequency dependent AC susceptibility measurements, confirms the existence of canonical spin glass at T<145 K. The occurrence of canonical spin glass has been explained in terms of the nanostructuring modified interactions between the FM correlations in the martensitic phase and the coexisting AFM.