Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSpontaneous magnetization and magnetic susceptibility of LaVO3
79
0
0.0
(
0
)
Authors
Hiroya Sakurai
Ask ChatGPT about the research
No Arabic abstract
Five characteristic temperatures of TM = 148 K, TN = 142 K, Tt = 138 K, Tf ~ 125 K and Tg ~ 50 K were found by the measurements of the magnetization curves at various temperature. The spontaneous magnetization appears below TM. It increases up to M_{S} simeq 2 times 10^{-4} mu_{B} at Tt and then decreases steeply below Tt, which qualitatively agrees with the temperature dependence of magnetization obtained under field-cooling (FC) condition. On the other hand, the slope of the magnetization curve, namely the magnetic susceptibility, drops below TN, which coincides with the temperature dependence of magnetization obtained under zero-FC condition, although the magnetization curves were obtained under FC condition. The temperature dependence of the spontaneous magnetization shows a minimum at Tf and a drop at Tg although there is no anomaly in the temperature dependence of FC or ZFC magnetization.
rate research
Read More
We report on the measurement of the magnetic susceptibility and of ESR transitions in the garnet substance Tb$_3$Ga$_5$O$_{12}$ (TGG). The results are compared with a calculation in the framework of crystal field theory for the orthorhombic surroundings of the six inequivalent Tb ions of TGG. We also present a calculation of the magnetization for the three main crystal directions.
We report the observation of spontaneous and ultra-sharp jumps in the low temperature magnetization isotherms of polycrystalline Nd5Ge3. Field-induced and ultra-sharp jumps are also seen in resistivity and heat capacity data. These jumps are accompanied by field-induced irreversibilities. The consistency seen in these three data clearly shows that the spin, electronic and lattice states are strongly coupled. Time-induced growth of the ferromagnetic phase is observed at a constant field and temperature, implying the metastability of the magnetic phase in the low field region. Various experimental findings point towards a strong field-induced magneto-structural irreversibility in this compound.
We analyzed the magnetic susceptibilities of several Cr spinels using two recent models for the geometrically frustrated pyrochlore lattice, the Quantum Tetrahedral Mean Field model and a Generalized Constant Coupling model. Both models can describe the experimental data for ACr2 O4 (with A = Zn, Mg, and Cd) satisfactorily, with the former yielding a somewhat better agreement with experiment for A = Zn, Mg. The obtained exchange constants for nearest and next-nearest neighbors are discussed.
The effect of pressure on magnetic properties of LaCoO$_3$ is studied experimentally and theoretically. The pressure dependence of magnetic susceptibility $chi$ of LaCoO$_3$ is obtained by precise measurements of $chi$ as a function of the hydrostatic pressure $P$ up to 2 kbar in the temperature range from 78 K to 300 K. A pronounced magnitude of the pressure effect is found to be negative in sign and strongly temperature dependent. The obtained experimental data are analysed by using a two-level model and DFT+U calculations of the electronic structure of LaCoO$_3$. In particular, the fixed spin moment method was employed to obtain a volume dependence of the total energy difference $Delta$ between the low spin and the intermediate spin states of LaCoO$_3$. Analysis of the obtained experimental $chi(P)$ dependence within the two-level model, as well as our DFT+U calculations, have revealed the anomalous large decrease in the energy difference $Delta$ with increasing of the unit cell volume. This effect, taking into account a thermal expansion, can be responsible for the temperatures dependence of $Delta$, predicting its vanishing near room temperature.
In the triangular layered magnet PdCrO2 the intralayer magnetic interactions are strong, however the lattice structure frustrates interlayer interactions. In spite of this, long-range, 120$^circ$ antiferromagnetic order condenses at $T_N = 38$~K. We show here through neutron scattering measurements under in-plane uniaxial stress and in-plane magnetic field that this occurs through a spontaneous lifting of the three-fold rotational symmetry of the nonmagnetic lattice, which relieves the interlayer frustration. We also show through resistivity measurements that uniaxial stress can suppress thermal magnetic disorder within the antiferromagnetic phase.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
