[en] Thin copper ferrite films have been deposited on amorphous quartz substrates. The films are annealed in air and either quenched in liquid nitrogen or slow cooled from the annealing temperature. The quenched as well as slow cooled films, show (1 1 1) peaks of copper ferrite along with the (3 1 1) peak. This indicates strong (1 1 1) orientation of the films. From the MH loops, squareness value (M_R/M_S) has been calculated for both type of films. The squareness value of the parallel MH loop is double the value of the perpendicular MH loop

[en] We have studied the magnetic compensation behaviour in the admixed series of Pr_1-xGd_xAl₂ alloys, with x = 0.15, 0.17, 0.2 and 0.25. The low field zero crossover and the high field turnaround in the magnetization response illustrates the competition between the contributions from Pr and Gd moments below the magnetic ordering temperature during the cooling process. The magnetic turnaround imprints as a phase transition in the heat capacity data. (author)

[en] The result of dc and ac magnetization, heat capacity and magneto-resistance measurements in the polycrystalline and single crystal samples at the stoichiometry, Nd_0.75Ho_0.25Al₂, are presented. Magnetic compensation between the antiferromagnetically coupled Nd and Ho moments in nominal zero field, and the field induced reorientation of the Nd/Ho moments in H = 5 kOe are observed to happen at the same temperature for H || [100], [110] and [111] directions. The ac magnetization data also appear to imprint the field-induced moment reversal process in polycrystalline as well as in a single crystal sample (for H || [100]). Intriguingly, the magneto-resistivity data in H = 10 kOe show three sign reversals below T_c.

[en] Reentrance in magnetic compensation has been observed for Nd_0.75Gd_0.25Rh₃B₂. Upto three crossovers in the sign of magnetization values are seen to occur below the nominal ordering temperature (∼46 K) of the alloy. The number of crossover temperatures, however, depend on the applied magnetic field. (author)

[en] Repeated magnetic compensation has been observed in the zero magnetization spin ferromagnetic stoichiometry Nd_0.8Tb_0.2Al₂. The ac susceptibility, heat capacity and transport measurements reveal the two underlying transitions in Nd_0.8Tb_0.2Al₂ alloy corresponding to the occurrence of the multiple magnetic compensations in the low field thermomagnetic response. (author)

[en] We report here on the discovery of novel features in a near-zero magnetization alloy, Nd_0.75Gd_0.25Rh₃B₂, which comprises two quasi-antiferromagnetic (or ferrimagnetic) transitions, and concomitantly repeated magnetic compensation feature, one after the other. The half-widths of the magnetization hysteresis loops associated with the (residual) remanent magnetization also has an oscillatory characteristic, with two local minima close to the two crossovers of the M = 0 axis in nominal zero field. We conjecture that the unusual observations arise from anisotropic hexagonal structure of the admixed compound, resulting in a quasi-one dimensional electronic structure, and due to the accentuated role of conduction electron polarization near the 'zero-magnetization' limit.

[en] Field induced reversal in orientations of magnetic moments is a characteristic of the 'zero magnetization spin - ferromagnets', comprising dissimilar rare earth moments combined with non-magnetic elements. Many interesting features are observed as a result of such a reorientation process. We present the sign reversal in Hall resistance across the magnetic compensation temperature in polycrystalline Pr_0.8Gd_0.2Al₂ alloy and also provide the microscopic evidence via the XMCD measurements for the field-induced reversal in the orientation of Pr and Gd moments in a single crystal sample. (author)

[en] A ferromagnetic rare earth (RE) intermetallic can be made to imbibe zero magnetization characteristic and display magnetic reorientation phenomenon by letting a RE site be occupied at random by two RE atoms belonging to different halves of 4f series (Gd to be counted along with second half) and choosing their fractional compositions appropriately. In recent times, H. Adachi and co-workers drew specific attention to ferromagnetic Sm based systems, where the net moment can be either 'orbital surplus', or 'spin surplus' (due to admixture effects) and the zero magnetization state can be obtained by substitution of Sm by the Gd or Nd. We present here a status report of our investigations and describe newer features related to magnetic compensation phenomenon in a wide variety of RE systems. In particular, our studies reveal that (i) the notion of spin flip transition across the temperature region of magnetic compensation is a generic behavior, (ii) it can happen in a re-entrant manner in specific circumstances, (iii) it survives strong hybridization effects that can happen for Ce³⁺ ions, e.g., in CeRh₃B₂, and compromise ferromagnetic exchange interaction between dissimilar RE spins, etc. (author)

[en] Magnetization studies in Nd_1-xTb_xAl₂ (x ≤ 0.25) series reveal the emergence of two well separated quasi-antiferromagnetic transitions near x ∼ 0.2. XMCD results show reversal in orientation of local moments at the second transition. Low field magnetization in a single crystal of Nd_0.8Tb_0.2Al₂ has confirmed the occurrence of repeated magnetic compensation. (author)

[en] The magnetization compensation phenomenon is observed for Sm_l-xNd_xScGe at x=0.09 at a temperature ∼ 90 K in a small applied magnetic field, which establishes the 'spin surplus' status of magnetic moment of Sm in the host matrix. We also noted that the sample profiles in QD SQUID magnetometer become asymmetric in some situations indicating significant contributions from multiple moments higher than the dipole moment. We have successfully accounted for them using a fitting procedure involving the higher order magnetic moments. (author)