2016/07/01 by N. S. Sangeetha, Eduardo Cuervo‐Reyes, Eduardo Cuervo-Reyes +2 · 3 citations
Chemistry · Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Anisotropy #Antiferromagnetism #Chemistry #Condensed matter physics #Crystal structure #Crystallography #Heat capacity #Heisenberg model #Iron-based superconductors research #Magnetic field #Magnetic susceptibility #Magnetization #Materials science #Neutron diffraction #Physics #Physics of Superconductivity and Magnetism #Quantum mechanics #Tetragonal crystal system #Thermodynamics #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.94.014422
published as Phys. Rev. B 94, 014422 (2016); 18 pages · 20 pages, 17 figures, 3 tables, 46 references. This is an extended replacement of arXiv:1512.02958 with an additional coauthor
openalex created_date 2016/06/24 · arxiv created 2016/07/01 · openalex publication_date 2016/07/19 · arxiv updated 2016/07/20 · openalex updated_date 2026/08/05
The metallic compound EuCo2P2 with the body-centered tetragonal ThCr2Si2 structure containing Eu spins-7/2 was previously shown from single-crystal neutron diffraction measurements to exhibit a helical antiferromagnetic (AFM) structure below TN=66.5 K with the helix axis along the c axis and with the ordered moments aligned within the ab plane. Here we report crystallography, electrical resistivity, heat capacity, magnetization, and magnetic susceptibility measurements on single crystals of this compound. We demonstrate that EuCo2P2 is a model molecular-field helical Heisenberg antiferromagnet from comparisons of the anisotropic magnetic susceptibility \ensuremathχ, high-field magnetization, and magnetic heat capacity of EuCo2P2 single crystals at temperature T\ensuremath≤TN with the predictions of our recent formulation of molecular-field theory. Values of the Heisenberg exchange interactions between the Eu spins are derived from the data. The low-T magnetic heat capacity \ensuremath∼T3 arising from spin-wave excitations with no anisotropy gap is calculated and found to be comparable to the lattice heat capacity. The density of states at the Fermi energy of EuCo2P2 and the related compound BaCo2P2 are found from the heat capacity data to be large, 10 and 16 states/eV per formula unit for EuCo2P2 and BaCo2P2, respectively. These values are enhanced by a factor of \ensuremath∼2.5 above those found from DFT electronic structure calculations for the two compounds. The calculations also find ferromagnetic Eu--Eu exchange interactions within the ab plane and AFM interactions between Eu spins in nearest- and next-nearest planes, in agreement with the MFT analysis of \ensuremathχab(T\ensuremath≤TN).