Noncollinear magnetic order and spin wave spectrum in presence of competing exchange interactions

1980 ◽  
Vol 15-18 ◽  
pp. 357-358 ◽  
Author(s):  
E. Rastelli ◽  
A. Tassi ◽  
L. Reatto
2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Narayan Mohanta ◽  
Andrew D. Christianson ◽  
Satoshi Okamoto ◽  
Elbio Dagotto

AbstractUnderstanding the spin-wave excitations of chiral magnetic order, such as the skyrmion crystal (SkX), is of fundamental interest to confirm such exotic magnetic order. The SkX is realized by competing Dzyaloshinskii-Moriya and ferromagnetic-exchange interactions with a magnetic field or anisotropy. Here, we compute the dynamical spin structure factor, using Monte Carlo and spin dynamics simulations, extracting the spin-wave spectrum in the SkX, in the vicinity of the paramagnet to SkX transition. Inside the SkX, we find six spin-wave modes, which are supplemented by another mode originating from the ferromagnetic background. Above the critical temperature Ts for the skyrmion crystallization, we find a diffusive regime, reminiscent of the liquid-to-crystal transition, revealing that topological spin texture of skyrmionic character starts to develop above Ts as the precursor of the SkX. We discuss the opportunities for the detection of the spin waves of the SkX using inelastic-neutron-scattering experiments in manganite-iridate heterostructures.


2015 ◽  
Vol 233-234 ◽  
pp. 3-7
Author(s):  
A.N. Ignatenko ◽  
Andrey A. Katanin ◽  
Valentin Yu. Irkhin

Thermodynamic properties of cubic Heisenberg ferromagnets with competing exchange interactions are considered near the frustration point where the coefficient D in the spin-wave spectrum Ek ~ Dk2vanishes. Within the Dyson-Maleev formalism it is found that at low temperatures thermal fluctuations stabilize ferromagnetism by increasing the value of D. For not too strong frustration this leads to an unusual "concave" shape of the temperature dependence of magnetization, which is in agreement with experimental data on the europium chalcogenides. Anomalous temperature behavior of magnetization is confirmed by Monte Carlo simulation. Strong field dependence of magnetization (paraprocess) at finite temperature is found near the frustration point.


Sign in / Sign up

Export Citation Format

Share Document