H-1 NMR on (NixMn1-x)(3)[Cr(Cn)(6)](2) center dot NH(2)O

We report on H-1 NMR of (NixMn1-x)(3)[Cr(Cn)(6)](2) center dot nH(2)O hexacyanochromates, where x changes from 0 to 1. The decay time constants of the free induction decay signals described by an effective spin-spin relaxation time T-2eff obtained from M(t) = M-0 exp(t/T-2eff) decrease as the local magnetic moments increase produced by the magnetic transition metal ions at the sites of the resonant H-1 nuclei. The recovery of the magnetization in the spin-lattice relaxation time (T-1) experiments was single-exponential

Crystal Structure and Magnetocaloric Effect of La0.80Ag0.15MnO3 Nanoparticles

Annealing of_ non stoichiometric La0.80Ag0.15MnO3 nanoparticles leads to the change of the crystal symmetry from Pnma to R3c and to almost doubling of its Curie temperature from 117 K to 317 K. This effect is due to the releasing of lattice distortions and strengthening of double exchange interaction. The large values of the magnetocaloric entropy of the order of ∆S = 6.19 J/(kg K) were observedat ∆µ0H = 5 T and T = 315 K.Proceedings of the 17th Czech and Slovak Conference on Magnetism, Košice, Slovakia, June 3–7, 2019

An ac susceptibility study of spin dynamics in a super spin glass nanoparticle La0.7Ca0.3MnO3 system: simultaneous relaxation processes

In this paper, we present the results of a systematic study of nonequilibrium dynamics in a strongly interacting super spin glass (SSG) nanoparticle La0.7Ca0.3MnO3 system by alternating current (ac) susceptibility measurements. Cole-Cole analysis of the obtained data revealed the simultaneous existence of two separated relaxation processes, which can be assigned to the relaxation of different magnetic entities. Along with the expected relaxation of the collective SSG phase, the existence of individual, nonagglomerated particles, which do not take part in the collective phase and relax independently, was proposed. A full dynamical scaling analysis was performed in order to elucidate the nature of the transition to a low-temperature SSG state in the interacting La0.7Ca0.3MnO3 nanoparticle sample

Magnetism of Nanoparticle La0 7Ca0 3Mn0 7Fe0 3O3 under Applied Hydrostatic Pressure

Nanoparticle La0 7Ca0 3Mn0 7Fe0 3O3 with the average particle size of 10 nm was mechanochemically synthesized in the single-step procedure Temperature and field dependences of magnetization were recorded under both ambient and applied hydrostatic pressure up to 0 47 GPa At ambient pressure, two magnetic transition points were observed one of the spin-glass like type at the temperature T-f approximate to 34 K, and ferro-to-paramagnet transition at T-C approximate to 51 K Under the applied pressure magnetic parameters gradually changed (i) both T-C and T-f were lowered with the increase in pressure, (ii) both high field magnetization M-5T and remanent magnetization M-Rem decreased with pressure, (iii) coercivity H increased with pressure The obtained results show that magnetism of a nanoparticle system with high degree of Intrinsic disorder diminishes with the applied pressure that is in compliance with the effect of the increased cationic disorder (internal pressure) in bulk manganites14th Czech and Slovak Conference on Magnetism, Jun 06-09, 2010, Kosice, Slovaki

Magnetic Properties of NdFe0.9Mn0.1O3

In our paper we study effect of Mn for Fe substitution on magnetic properties of NdFex-1MnxO3 compounds for x = 0 and 0.1, which have been grown by the OFZ technique. The Neel temperature decreases from T-N1 = 691 K to T-N1 = 621 K, and the anomaly in AC susceptibility, related to spin reorientation, vanishes with Mn substitution. Low temperature heat capacity measurement for sample with x = 0.1 revealed that substitution of Mn for Fe shifts a Schottky-type anomaly at T-sh to higher temperatures. Another anomaly is generated by doping at T-max = 11 K. The anomaly is smeared out by magnetic field, confirming its magnetic origin.15th Czech and Slovak Conference on Magnetism (CSMAG), Jun 17-21, 2013, Kosice, Slovaki

Exchange Bias Effect in NdFeO3 System of Nanoparticles

We study the effect of nanometric size on the crystal structure, magnetic environment of iron and magnetization in NdFeO3 system of nanoparticles. The average particle size of NdFeO3 nanoparticles increases with annealing at 600 degrees C from about 15 nm to 40 nm, The smallest particles on annealed sample have size approximately 30 nm and typically have character of single crystalline samples. All samples adopt orthorhombic crystal structure, space group Prima with lattice parameters a = 5.5817 angstrom, b = 7.7663 angstrom and c = 5.456 angstrom for as prepared sample. The presence of superparamagnetic particles was indicated by the Mossbauer measurements. The reduction of dimensionality induces a decrease of T-N1 from 691 K to 544 K. The shift of magnetic hysteresis loop in vertical and horizontal direction was observed at low temperatures after cooling in magnetic field. We attribute such behaviour to exchange bias effect and discuss in the frame of core shellmodel.16th Czech and Slovak Conference on Magnetism (CSMAG), Jun 13-17, 2016, Kosice, Slovaki

Magnetic Properties and Mossbauer spectroscopy of NdFe(1-x)MnxO(3)

The effect of particle reduction to nanoscale size and substitution of Mn3+ ions for Fe3+ ions on the crystal structure, lattice dynamics, Mossbauer spectra and magnetic properties in NdFe(1-x)MnxO(3) compounds have been studied. X-ray powder diffraction and Raman spectroscopy revealed that the Jahn-Teller distortion of lattice dominates for samples with x GT 0.4. The average particle size of NdFeO3 nanoparticles (NAP) increases with annealing at 600 degrees C from about 15 nm to 25 nm. The presence of superparamagnetic particles was indicated by Mossbauer measurements in NdFeO3 NAP system. Sextets in NdFe(1-x)MnxO(3) Mssbauer spectra can be modelled with several local environments of Fe3+ induced by substitution. The reduction of dimensionality and the substitution induce a decrease of the Neel temperature T-Nl from 691 K to 544 K for NAP or to 356 K for x = 0.4, however the temperature of spin reorientation T-SR increases with substitution. The saturated magnetization obtained at 1.9 K increases and ferromagnetic component is removed below T-SR with the substitution.International Conference on Strongly Correlated Electron Systems (SCES), Jul 07-14, 2014, Univ Grenoble, Grenoble, Franc