EPJ Web of Conferences 185, 05004 (2018)
https://doi.org/10.1051/epjconf/201818505004

Visualization of magnetostructural transition in Heusler alloys by Magnetic Force Microscopy

¹ School of Engineering Science, Lappeenranta University of Technology (LUT), 53850 Lappeenranta, Finland
² Faculty of Physics, Lomonosov Moscow State University (MSU), 119991 Moscow, Russia
³ Physics and Materials Science Research Unit, University of Luxembourg, 4365 Luxembourg, Luxembourg
⁴ Department of Physics, Southern Illinois University, Carbondale, IL 62901, USA

^* Corresponding author: pavel.geydt@gmail.com

Published online: 4 July 2018

Abstract

Magnetostructural transition was observed in Ni-Mn-In-Cr Heusler alloy with help of Magnetic Force Microscopy (MFM). The crystal structure of a sample and characteristic temperatures of the phase transition were controlled by roentgenostructural phase analysis and magnetometry, respectively. It appeared prominently important to prepare the surface of the sample until the nanometer level of surface roughness. Magnetic study performed with scanning probe microscope revealed existence of magnetic domains, which were spread across the surface evenly. Further studies revealed that intensity of magnetic signal decreases as fading out of the contrast of the MFM images. It was found that location of domains shifted after the heating/cooling cycle above Curie temperature for the studied alloy. Location of new domain walls appeared correlating with surface scrapings and defects, whilst it became independent from those after heating until just 70°C. The mechanism behind the observed transition is proposed.