Magnetization Of Group Research Articles

Half-metallic ferromagnetism in (C, Si, Ge, Sn and Pb)-doped I 2–VI compounds: An ab initio study

First-principles calculations were performed to investigate the stability, electronic structure and magnetism in Group IV elements-doped alkali-metal oxides (M 2O) [M: Li, Na, K, Rb] in antifluorite structure using the linear muffin-tin orbital method in its tight-binding representation (TB-LMTO). The calculations reveal that non-magnetic dopants can induce stable half-metallic ferromagnetic ground state in I 2–VI compounds. Total energy calculations show that the ferromagnetic state is energetically more stable than the non-magnetic state at equilibrium volume. Ground state properties such as equilibrium lattice constant and bulk modulus were calculated. The magnetic moment is found to be 2.00 μ B per dopant atom.

Paleomagnetism of Metamorphic Rocks of Daly Bay and Melville Peninsula, Churchill Structural Province

Studies of metamorphic rocks from the Daly Bay and Melville Peninsula areas of the Churchill Structural Province of the Canadian Shield have yielded two groups of directions. Group A directions (16 sites) from gneisses of basic and intermediate composition have the mean 196°, +55 °(N = 16, k = 39, α95 = 6.1°) with a corresponding pole at 12°N, 101°W (k = 27, α95 = 7°). These rocks are foliated and the average effect of anisotropy on the high coercive force (stable) components is small. Evidence is presented to show that agewise the pole falls within the range of 1250 to 2100 m.y. The pole lies on the apparent polar wander curve for the Canadian Shield in the time range 1425 to 1725 m.y. which defines its age within narrower limits. Since the mean K–Ar age is 1622 ± 30 m.y., the magnetization of Group A may reflect this age. This result shows that metamorphic rocks can be used to provide useful paleomagnetic data. The Group B magnetization, however, derived mainly from acidic gneisses and having a mean direction of 055°, +72 °(N = 8, k = 18, α95 = 13°) and a pole at 67°N, 009°W very close to the present pole, is probably of recent origin.