J1-2118 — Final report
1.
Role of antisymmetric exchange in selecting magnetic chirality in Ba[sub]3NbFe[sub]3Si[sub]2O[sub](14)

We presented an electron spin resonance (ESR) investigation of the acentric Ba3NbFe3Si2O14, featuring a unique single doma in double chiral magnetic ground state. Combining simulations of the ESR linewidth anisotropy and the antiferromagneticresonance modes allows us to single out the Dzyaloshinsky-Moriya (DM) interaction as the leading magnetic anisotropy term. We demonstrate that the rather minute out-of-plane DM component dc=45 mK is responsible for selecting a unique ground state, which endures thermal fluctuations up to astonishingly high temperatures.

COBISS.SI-ID: 25416231
2.
Ground state of the easy-axis rare-earth kagome langasite Pr[sub]3Ga[sub]5SiO[sub](14)

Employing muon spin relaxation technique, we have showed that the magnetic ground state of the rare-earth bases langasites critically depends on the nature of the rare-earth. For nonKramers ion Pr3+ (J=4) the ground state is a nonmagnetic crystal-field singlet. Despite that fact, small quasistatic random internal fields develop below 40 K and persist down to at least 21 mK. These originate from strongly hyperfine-enhanced 141Pr nuclear magnetism.

COBISS.SI-ID: 23389991
3.
Spin configuration in the 1/3 magnetization plateau of azurite determination by NMR

High magnetic field 63,65Cu NMR spectra were used to determine the local spin polarization in the 1/3 magnetization plateau of azurite, Cu3 (CO3)2(OH)2, which is a model system for the distorted diamond antiferromagnetic spin1/2 chain.

COBISS.SI-ID: 22562855
4.
Persistent spin dynamics Intrinsic to amplitude-modulated long-range magnetic order

An incommensurate elliptical helical magnetic structure in the frustrated coupled-spin-chain system FeTe2O5Br is surprisingly found to persist down to 53(3) mK (T/T_N = 1/200), according to neutron scattering and muon spin relaxation. In this state, finite spin fluctuations at T → 0 are evidenced by muon depolarization, which is in agreement with specific-heat data indicating the presence of both gapless and gapped excitations. We thus show that the amplitude-modulated magnetic order intrinsically accommodates contradictory persistent spin dynamics and long-range order and can serve as a model structure to investigate their coexistence.

COBISS.SI-ID: 26300711
5.
Quantum-critical spin dynamics in quasi-one-dimensional antiferromagnets

Using spin-lattice relaxation we found out that the spin dynamics in two different quasi-1D quantum spin systems is identical, which demonstrates the theoretically predicted universality of the quantum critical behavior.

COBISS.SI-ID: 26220327