Observation of Griffiths phase in antiferromagnetic La(0.32)Eu(0.68)MnO3

Observation of Griffiths-like phase in the quaternary Heusler compound NiFeTiSn

The quaternary Heusler compound NiFeTiSn can be considered to be derived from the exotic pseudogap-compound Fe₂TiSn by the replacement of one Fe atom by Ni. In contrast to Fe₂TiSn, which shows a disorder induced ferromagnetic phase, the ground state of NiFeTiSn is antiferromagnetic with the signature of spin canting. Interestingly, NiFeTiSn shows a Griffiths-like phase characterized by isolated ferromagnetic clusters before attaining the antiferromagnetic state. The Griffiths-like phase is possibly associated with the antisite disorder between Fe and Ti sites as evident from our powder x-ray diffraction study. The compound also shows rather unusual temperature dependence of resistivity, which can be accounted by the prevailing structural disorder in the system. NiFeTiSn turned out to be a rare example where Griffiths-like phase is observed in a semiconducting 3dtransition metal based intermetallic compound with antiferromagnetic ground state.

Structural correlation to ferroelectric order, non-Griffiths like phase and magnetocaloric effect in YbCrO4

We report a ferroelectric order around ∼99 K (T_FE), which is considerably above the long range ferrimagnetic order at 25 K (T_N). The value of saturation electric polarization is considerable as ∼570μC m^-2for a poling field of 5 kV cm^-1. The ferroelectric order is associated with a significant magnetoelectric coupling below ∼90 K. A weak signature ofT_FEis observed in the dielectric constant, which is associated with a linear magnetodielectric response at 18 K(<TN). A transition to a polar structure has been correlated with the occurrence of ferroelectric order. A non-Griffiths like phase is observed around ∼48 K, which is also linked with the structural distortion. A reasonable value of the magnetic entropy change of 5.07 J Kg^-1 K^-1is noted atT_Nfor a change in field of 50 kOe, which involves a strong magnetoelastic coupling. The results indicate considerable structural instabilities, which is linked with the observed multifunctional properties of YbCrO₄.

Significant magneto-elastic coupling at Griffiths-like phase boundaries in low dimensional oxides,ASb2O6(ANi and Mn)

The compounds, NiSb₂O₆(NSO) and MnSb₂O₆(MSO) attract the community for the quasi one-dimensional and layered structure composed of Ni²⁺and Mn²⁺, which orders antiferromagnetically atT_N= 6.7 and 12 K, respectively. Here, we report the Griffiths-like phase much aboveT_Nin the range of 37-85 K and 25-80 K for NSO and MSO, respectively. The dc magnetization results indicate the Griffiths-like phase, following the modified Curie-Weiss law. The magneto-capacitive responses for both the compounds show anomalies at the onset of the Griffiths-like phase. Intriguingly, the low temperature synchrotron diffraction results are conclusive for determining the singularities for both the compounds. Interplay between the low-dimensionality, magnetic frustration, and magneto-elastic coupling correlates the observed short range ordered state, which is suggested as a Griffiths-like phase, aboveT_Nfor both the compounds.

Impact of synthesis route on structural, magnetic, magnetocaloric and critical behavior of Nd0.6Sr0.4MnO3 manganite

Nd0.6Sr0.4MnO3 polycrystalline manganite was synthesized by two different methods: the auto-combustion reaction (NSMO-AC) and the sol-gel method (NSMO-SG). The structural, magnetic, magnetocaloric and critical behavior of the samples were examined. Rietveld refinements of the XRD patterns revealed that both compounds are pure single phase indexed to the orthorhombic system adopting the Pnma space group. The nanometric size estimated using the Williamson-Hall method was confirmed by TEM micrographs. Magnetic measurements as a function of temperature indicated that both samples underwent a second order ferromagnetic (FM)-paramagnetic (PM) phase transition at Curie temperature (T C). The relative cooling power was observed to be around 95.271 J kg-1 for NSMO-AC and 202.054 J kg-1 for NSMO-SG at μ 0 H = 5 T, indicating that these materials are potential candidates for magnetic refrigeration application close to room temperature. The critical behavior was estimated using diverse techniques based on the isothermal magnetization data recorded around the critical temperature T C. The calculated values are fully satisfactory to the requirements of the scaling theory, implying their reliability. The estimated critical exponents matched well with the values anticipated for the mean-field model and the 3D Ising model for NSMO-AC and NSMO-SG, respectively, showing that the magnetic interactions depended on the process of elaboration.