Related papers: Fluctuation Effects on the Quadrupolar Ordering in…
We observe a disappearance of the 1/3 magnetization plateau and a striking change of the magnetic configuration under a moderate doping of the model triangular antiferromagnet RbFe(MoO4)2. The reason is an effective lifting of degeneracy of…
The two-dimensional model of itinerant electrons coupled to an anti-ferromagnetic order parameter is considered. In the mean field solution the Fermi surface undergoes reconstruction, and breaks into disconnected ``pockets''. We have…
In this contribution we would like to revisit the problems of ferromagnetism (F) and antiferromagnetism (AF) in the pure itinerant model. These methods can be extended later to the superconducting materials. In our model we assume the…
We study ordering mechanisms which are induced by the quantum fluctuation in fully frustrated Ising spin systems. Since there are many degenerated states in frustrated systems, "order by thermal disorder" often takes place due to a kind of…
Exchange interaction within a quantum dot strongly affects the transport through it in the Kondo regime. In a striking difference with the results of the conventional model, where this interaction is neglected, here the temperature and…
We analyze a microscopic origin of the Kondo effect-assisted orbital order in heavy-fermion materials. By studying the periodic two-orbital Anderson model with two local electrons, we show that frustration of Hund's rule coupling due to the…
The possibility is investigated that competition between fluctuations at different symmetry-related ordering wave vectors may affect the quantum phase transition between a fermi liquid and a longitudinal spin density wave state, in…
We investigate the effect of external pressure on magnetic order in undoped LnFeAsO (Ln = La, Ce, Pr, La) by using muon-spin relaxation measurements and ab-initio calculations. Both magnetic transition temperature $T_m$ and Fe magnetic…
Multiferroic TbMnO3 is investigated using x-ray diffraction in high magnetic fields. Measurements on first and second harmonic structural reflections due to modulations induced by the Mn and Tb magnetic order are presented as function of…
This work studies the influence of an external magnetic field on hadron yields and fluctuations in a hadron resonance gas by performing calculations within an updated version of the open-source Thermal-FIST package. The presence of the…
We have used element specific X-ray resonant scattering to investigate the M edge resonances in a single crystal of \unpo. Earlier neutron diffraction and M\"{o}ssbauer studies had shown the presence of long-range AF order below T$_{N}$ =…
We examine the effect of classical magnetic fluctuations on the phase diagram of paramagneticallylimited two-dimensional superconductors under a Zeeman magnetic field. We derive the free energy expansion in powers of the superconducting…
The origin of non-collinear magnetic order in UO$_{2}$ is studied by an ab initio dynamical-mean-field-theory framework in conjunction with a linear-response approach for evaluating inter-site superexchange interactions between U 5$f^{2}$…
Motivated by recent experiments on Mott insulators, in both iridates and ultracold atoms, we theoretically study the effects of magnetic order on the Mott-Hubbard excitons. In particular, we focus on spin-mediated doublon-holon pairing in…
Effect of randomness in the double-exchange model is studied. Large fluctuations and spatial random distribution of impurities are taken into account in an essentially exact manner by using the Monte Carlo calculation. The randomness…
In non-Kramers Kondo systems with a quadrupolar degrees of freedom, an ordinary magnetic Kondo effect can compete with the quadrupolar Kondo effect. We discuss such competition keeping Pr$T_{2}$Zn$_{20}$ ($T$=Ir, Rh) and Pr$T_{2}$Al$_{20}$…
It is shown that ferromagnetic ordering in metals is associated with an opening of the energy pseudogap. This energy pseudogap belongs to a d-band type in d-metals and to an sp-band type in f-metals. A relation between the magnetic energy…
Using neutron diffraction, we have studied the magnetic field effect on charge structures in the charge-ordered multiferroic material LuFe$_2$O$_4$. An external magnetic field is able to change the magnitude and correlation lengths of the…
We investigate a competition of tendencies towards ferromagnetic and incommensurate order in two-dimensional fermionic systems within functional renormalization group technique using temperature as a scale parameter. We assume that the…
Magnetic fluctuations near to quantum criticality can have profound effects. They lead to characteristic scaling at high temperature which may ultimately give way to a reconstruction of the phase diagram and the formation of new phases at…