Niharika Mohapatra

Magnetic anomalies in the spin-chain compound Sr 3 Cu Rh O 6 : Griffiths-phase-like behavior of magnetic susceptibility

We report the results of ac and dc magnetic susceptibility (chi), heat-capacity (C), isothermal magnetization and isothermal remanent magnetization measurements on the compound, Sr3CuRhO6, crystallizing in a K4CdCl6-derived monoclinic structure. The magnetization data reveal distinct magnetic anomalies near 6 and 12 K with decreasing temperature (T). While the transition below (To=) 6K appears to be of a spin-glass-type as inferred from all the data, the one at 12 K is not typical of bulk ferromagnetism in contrast to an earlier proposal. In the range 6 to 12 K, the dc chi obeys the theoretically expected form for very low dc fields and the values of chi decrease gradually with the application of higher magnetic fields, mimicking the behavior Griffiths-phases.

A first-order magnetic phase transition near 15 K with novel magnetic-field-induced effects in Er5Si3

We present magnetic characterization of a binary rare-earth intermetallic compound Er(5)Si(3), crystallizing in Mn(5)Si(3)-type hexagonal structure, through magnetization, heat capacity, electrical resistivity and magnetoresistance measurements. Our investigations confirm that the compound exhibits two magnetic transitions with decreasing temperature, the first one at 35 K and the second one at 15 K. The present results reveal that the second magnetic transition is a disorder-broadened first-order transition, as shown by thermal hysteresis in the measured data. Another important finding is that, below 15 K, there is a magnetic-field-induced transition with a hysteretic effect with the electrical resistance getting unusually enhanced at this transition and the magnetoresistance is found to exhibit intriguing magnetic-field dependence, indicating novel magnetic phase coexistence phenomenon. It thus appears that this compound is characterized by interesting magnetic anomalies in the temperature-magnetic-field phase diagram.

Multiferroicity and magneto-electric effect in Gd2BaNiO5

We report the observation of electric polarization in the magnetically ordered state of the Haldane chain compound, Gd2BaNiO5, with strongly correlated magnetic and dielectric properties. The results of dc magnetic susceptibility and heat capacity measurements indicate two magnetic transitions, one corresponding to the anti-ferromagnetic order at TN ∼ 55 K and the other to spin-reorientation transition at TSR ∼ 24 K. The dielectric permittivity (ϵr′) and loss (tanδ) also exhibit anomalies in the vicinity of TSR and TN, respectively. Below the spin-reorientation transition, concurrently magnetic-field-induced spin-flop and the meta-electric transitions are observed at a critical magnetic field in isothermal magnetization and magneto-dielectric results, respectively. Another interesting finding is that Δϵr′ (=(ϵr′(H)−ϵr′(0))/ϵr′(0)) changes its sign at the critical magnetic field. The origin of the observed magneto-electric effect is discussed on the basis of spin–phonon coupling.

Influence of pressure on the magnetic behavior and the anomalous magnetoresistance in Tb 5 Si 3

The compound,

Magnetic and dielectric behavior of the spin-chain compound Er2BaNiO5 well below its Néel temperature

{\text{Tb}}_{5}{\text{Si}}_{3}

Anomalous butterfly-shaped magnetoresistance loops in the alloy Tb 4 LuSi 3

, crystallizing in

Magnetic and magnetodielectric coupling anomalies in the Haldane spin-chain system Nd2BaNiO5

{\text{Mn}}_{5}{\text{Si}}_{3}

Stability of the geometrically frustrated magnetic state of Ca3CoRhO6 to applications of positive and negative pressure

-type hexagonal structure, was recently reported by us to exhibit a sudden and huge enhancement in electrical resistivity

Magnetism of fine particles of Kondo lattices, obtained by high-energy ball-milling

(\ensuremath{\rho})

Heavy Fermion Behaviour in Ce2Ni1.88Cd

at a critical magnetic field