title: Magnetic relaxation dynamics driven by the first-order character of magnetocaloric La(Fe,Mn,Si)13.
abstract: Here, we study the temporal evolution of the magnetic field-driven paramagnetic to ferromagnetic transition in the La(Fe,Mn,Si)13 material family. Three compositions are chosen that show varying strengths of the first-order character of the transition, as determined by the relative magnitude of their magnetic hysteresis and temperature separation between the zero-field transition temperature Tc and the temperature Tcrit, where the transition becomes continuous. Systematic variations in the fixed field, isothermal rate of relaxation are observed as a function of temperature and as a function of the degree of first-order character. The relaxation rate is reduced in more weakly first-order compositions and is also reduced as the temperature is increased towards Tcrit At temperatures above Tcrit, the metastability of the transition vanishes along with its associated temporal dynamics.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.
authors.affiliation: Blackett Laboratory, Imperial College London, London SW7 2AZ, UK.
authors.forename: Edmund
authors.initials: E
authors.lastname: Lovell
authors.affiliation: Blackett Laboratory, Imperial College London, London SW7 2AZ, UK.
authors.forename: Milan
authors.initials: M
authors.lastname: Bratko
authors.affiliation: Blackett Laboratory, Imperial College London, London SW7 2AZ, UK.
authors.forename: A David
authors.initials: AD
authors.lastname: Caplin
authors.affiliation: Vacuumschmelze GmbH & Co. KG, Hanau, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Barcza
authors.affiliation: Vacuumschmelze GmbH & Co. KG, Hanau, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Katter
authors.affiliation: Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-972, Brazil.
authors.forename: Luis
authors.initials: L
authors.lastname: Ghivelder
authors.affiliation: Blackett Laboratory, Imperial College London, London SW7 2AZ, UK l.cohen@imperial.ac.uk.
authors.forename: Lesley F
authors.initials: LF
authors.lastname: Cohen
keywords: magnetic refrigeration; magnetic relaxation; magnetocaloric effect; metamagnetic transition