skip to main content

Title: Dynamics of the magneto structural phase transition in La(Fe{sub 0.9}Co{sub 0.015}Si{sub 0.085}){sub 13} observed by magneto-optical imaging

We investigate the temperature induced ferromagnetic to paramagnetic phase transition in Co substituted La(Fe{sub x}Co{sub y}Si{sub 1−x−y}){sub 13} with x = 0.9 and low Co content of y = 0.015 (T{sub c}≃200 K) by means of magneto-optical imaging with indicator film and by calorimetry at very low temperature rates. We were able to visualize the motion of the ferromagnetic (FM)/paramagnetic (PM) front which is forming reproducible patterns independently of the temperature rate. The average velocity of the FM/PM front was calculated to be 10{sup −4} m/s during the continuous propagation and 4×10{sup −3} m/s during an avalanche. The heat flux was measured at low temperature rates by a differential scanning calorimeter and shows a reproducible sequence of individual and separated avalanches which occurs independently of the rate. We interpret the observed effects as the result of the athermal character of the phase transition.
Authors:
;  [1] ;  [1] ;  [2] ; ;  [3]
  1. Istituto Nazionale di Ricerca Metrologica (INRIM), Strada delle Cacce 91, 10135 Turin (Italy)
  2. (Italy)
  3. Department of Applied Science and Technology, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Turin (Italy)
Publication Date:
OSTI Identifier:
22273783
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CALORIMETRY; COBALT SILICIDES; CONCENTRATION RATIO; FERROMAGNETISM; HEAT FLUX; IRON COMPOUNDS; LANTHANUM COMPOUNDS; MAGNETO-OPTICAL EFFECTS; PARAMAGNETISM; PHASE TRANSFORMATIONS; TEMPERATURE DEPENDENCE; THIN FILMS