Nucleation, instability, and discontinuous phase transitions in monoaxial helimagnets with oblique fields

Laliena, V. ; Campo, J. (Universidad de Zaragoza) ; Kousaka, Y.

Resumen: The phase diagram of the monoaxial chiral helimagnet as a function of temperature (T) and magnetic field with components perpendicular (Hx) and parallel (Hz) to the chiral axis is theoretically studied via the variational mean-field approach in the continuum limit. A phase transition surface in the three-dimensional thermodynamic space separates a chiral spatially modulated phase from a homogeneous forced ferromagnetic phase. The phase boundary is divided into three parts: two surfaces of second-order transitions of instability and nucleation type, in DeGennes terminology, are separated by a surface of first-order transitions. Two lines of tricritical points separate the first-order surface from the second-order surfaces. The divergence of the period of the modulated state on the nucleation transition surface has a logarithmic behavior typical of a chiral soliton lattice. The specific heat diverges on the nucleation surface as a power law with logarithmic corrections, while it shows a finite discontinuity on the other two surfaces. The soliton density curves are described by a universal function of Hx if the values of T and Hz determine a transition point lying on the nucleation surface; otherwise, they are not universal.

Idioma: Inglés

DOI: 10.1103/PhysRevB.95.224410

Año: 2017

Publicado en: Physical Review B 95 (2017), 224410 [9 pp]
ISSN: 2469-9950

Factor impacto JCR: 3.813 (2017)

Categ. JCR: PHYSICS, CONDENSED MATTER rank: 18 / 67 = 0.269 (2017) - Q2 - T1

Financiación: info:eu-repo/grantAgreement/ES/MINECO/MAT2015-68200-C2-2-P

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Física Materia Condensada (Dpto. Física Materia Condensa.)