Chanchal K. Majumdar

TL;DR: In this paper, the ground state properties of the Hamiltonian H = 12J ∑ i=1N σi·σi+1 + 12Jα ∑ n σI·σI+2 for both signs of J and −1 ≤ α ≤ 1 to gain insight into the stability of the ground states with nearest-neighbor interactions only (α = 0) in the presence of the next-nearest-nighbor interaction.

TL;DR: In this article, a soluble model of a gas of independent fermions in the presence of an attractive localized potential was considered, and it was shown that the properties of the system as a whole are smooth (analytic) functions of the potential.

TL;DR: In this article, single phase magnetite powders with crystallite sizes ranging from 8-50 nm were synthesized and studied using X-ray diffraction and Mossbauer spectroscopy.

TL;DR: A series of gels with nominal composition Fe2−xCrxO3 (x=0-2) was prepared at room temperature by an inorganic sol-gel route and studied by X-ray diffraction and Mossbauer spectroscopy.

TL;DR: The theory of positron annihilation in metals, including electron-positron and electron-electron interaction, is discussed in this article, where it is established that a sharp "break" in the angular-correlation curve of the two $\ensuremath{\gamma}$ rays resulting from the singlet-state annihilation occurs at precisely those angles where it should be expected in the absence of electron positron interaction.