Room temperature soft ferromagnetism in the nanocrystalline form of YCo2 - a well-known bulk Pauli paramagnet

The Laves phase compound, YCo2, is a well-known exchange-enahnced Pauli paramagnet. We report here that, in the nanocrystalline form, this compound interestingly is an itinerant ferromagnet at room temperature with a low coercive-field. The magnitude of the saturation moment (about 1 Bohr-magneton per formula unit) is large enough to infer that the ferromagnetism is not a surface phenomenon in these nanocrystallites. Since these ferromagnetic nanocrystallines are easy to synthesize with a stable form in air, one can explore applications, particularly where hysteresis is a disadvantage

Effect of addition of Co on the magnetic properties of MnSb

The influence of addition of Co on the structural and magnetic properties of MnSb was investigated. The compound formed in the NiAs-type hexagonal structure. Addition of Co to MnSb causes changes in both the lattice parameters. It was observed, from magnetization measurements, that both Curie temperature and saturation magnetization decrease from those of MnSb. The spin-polarized density of states (DOS) calculations revealed that the intermetallic compound favors ferromagnetic ground state even after as much as 0.25 atom of Co per formula unit of MnSb. Charge transfer takes place from the interstitial Co-atom to minority spin band of Mn-atom resulting in an increase in the DOS compared to MnSb at the Fermi level. MnSbCo0.25 exhibits a negative magnetocaloric effect with the largest change in the entropy value, ΔSm = 2.5 J. kg-1. K-1 (for a change in magnetic field from 0 to 5 T), across the second order phase transition at 292 K. The change in the value of magnetic entropy is low around the phase transition and might be due to the small magnetic moment of Mn-atom

Structural magnetic and magnetostrictive properties of Tb0.3Dy0.7 - xNdxFe1.93 [x = 0, 0.05, 0.1, 0.15 and 0.2] compounds

We report on the results pertinent to structural, magnetic, magnetostrictive studies of the Tb0.3Dy0.7 - xNdxFe1.93 [x = 0, 0.05, 0.1, 0.15 and 0.2] compounds. From the evidenced magnetization and magnetostriction results, the crucial finding that we emphasize is that the realization of minimum anisotropy for the compound with the composition x = 0.1. From the X-ray diffraction on magnetically aligned samples, (4 4 0) peak splitting analysis and Mössbauer studies, we ascertain that the easy magnetization direction (EMD) for x = 0.2 compound it is towards 〈1 1 0〉. Above results also affirmed that indeed there exists transformation of the structural distortion from rhombohedral to orthorhombic from x = 0 to x = 0.2. The Laves phase compound Tb0.3Dy0.6Nd0.1Fe1.93 with a large magnetostriction (λ111 1270 × 10-6) and a low anisotropy may be a potential candidate for magnetostriction applications

Magnetoelectric effect of (100−x)BaTiO<SUB>3</SUB>-(x)NiFe<SUB>1.98</SUB>O<SUB>4</SUB> (x=20-80 wt%) particulate nanocomposites

The magnetoelectric (100-x)BaTiO3-(x)NiFe1.98O4 (x=20, 40, 60, and 80 wt%) particulate composites have been prepared and the effects of size and interface are studied through microscopy measurements. Large magnetoelectric voltage coefficient (α E) values accompanied by large piezoelastic coefficient, large magnetostrictive strain coefficient, and an adequate interface contact between the magnetic and electric phases were observed in these nanocomposites. The nanocomposite with x=40 has an aE value of 252 mV cm−1 Oe−1, which is the largest value for any particulate magnetoelectric composite, based on the available open literature

Spark plasma sintered Sm(2)Co(17)-FeCo nanocomposite permanent magnets synthesized by high energy ball milling

Nanocomposite Sm(2)Co(17)-5 wt% FeCo magnets were synthesized by high energy ball milling followed by consolidation into bulk shape by the spark plasma sintering technique. The evolution of magnetic properties was systematically investigated in milled powders as well as in spark plasma sintered samples. A high energy product of 10.2 MGOe and the other magnetic properties of M(s) = 107 emu g(-1), M(r) = 59 emu g(-1), M(r)/M(s) = 0.55 and H(c) = 6.4 kOe were achieved in a 5 h milled and spark plasma sintered Sm(2)Co(17)-5 wt% FeCo nanocomposite magnet. The spark plasma sintering was carried out at 700 degrees C for 5 min with a pressure of 70 MPa. The nanocomposite showed a higher Curie temperature of 955 degrees C for the Sm(2)Co(17) phase in comparison to its bulk Curie temperature for the Sm(2)Co(17) phase (920 degrees C). This higher Curie temperature can improve the performance of the magnet at higher temperatures