Asymmetric magnetic relaxation behavior of domains and domain walls observed through the FeRh first-order metamagnetic phase transition

Abstract

The phase coexistence present through a first-order phase transition means there will be finite regions between the two phases where the structure of the system will vary from one phase to the other, known as a phase boundary wall. This region is said to play an important but unknown role in the dynamics of the first-order phase transitions. Here, by using both x-ray photon correlation spectroscopy and magnetometry techniques to measure the temporal isothermal development at various points through the thermally activated first-order metamagnetic phase transition present in the near-equiatomic FeRh alloy, we are able to isolate the dynamic behavior of the domain walls in this system. These investigations reveal that relaxation behavior of the domain walls changes when phase coexistence is introduced into the system and that the domain wall dynamics is di↵erent to the macroscale behavior. We attribute this to the e↵ect of the exchange coupling between regions of either magnetic phase changing the dynamic properties of domain walls relative to bulk regions of either phase. We also believe this behavior comes from the influence of the phase boundary wall on other magnetic objects in the system.

Synergy Effect of Temperature, Electric and Magnetic Field on the Depth Structure of the Ferh/Batio3 Composite Multiferroic

“…Both the ferromagnetic and the antiferromagnetic FeRh phases were described with three microenvironments apiece, 2 BD and a sextet for FM; and 2 BD and a singlet for AFM phase. Despite the equilibrium binary phase diagram of Fe and Rh exhibits only AFM phase at the present atomic concentration and room temperature [26], the FM phase is common in the case of thin films and is attributed to the small lattice mismatch between the BTO and the FeRh, as it was previously reported [47,49,62,63,64]. The last component; a very broad (unresolved) singlet, with intensity of 9 %; was associated to an unspecified oxide phase on the surface of the sample.…”

A method to assess the quality of additive manufacturing metal powders using the triboelectric charging concept

“…Data tting yielded averaged calculated β values of ~ 1.5. Interestingly, this value was used previously by other researchers to describe systems that exhibit "jammed" dynamics [43]. Examples of these systems are said to be structural glasses, colloidal gels, entangled polymers, and supercooled liquids, which experience jamming when motion of individual particles become restricted, causing their motion to slow down [44].…”

Characterisation of magnetic relaxation on extremely long timescales

“…Magnetisation decay data should be fit to eqn (2) with M 0 fixed to the first point measured in the target field and M eq fixed to the calculated target value; only if 99% of the decay is measured can M eq be reliably freely fit. The relaxation time from magnetisation decays is best described by e hln[t]i (eqn (9)), with ESDs defined by the logarithmic variance (eqn (13)). This measure of t is commensurate with t Debye derived from the waveform technique of Hilgar et al, and results in a chemically reasonable interpretation of the temperaturedependence of relaxation rates for [Dy(Dtp) 2 ][Al{OC(CF 3 ) 3 } 4 ], unlike the previous use of t* alone.…”

“…1). 10 For instance, b in eqn (2) is known to represent distributions in samples when the SEF is used for the analysis of supercapacitor discharge, 11,12 X-ray photon correlation spectroscopy, 13 and can indicate the onset of longrange-order in m-SR measurements. 14 The stretched exponential function is also used extensively in the study of spin-glass phenomena 15,16 and NMR measurements.…”