paper

Antiferromagnetic Stacking of Ferromagnetic Layers and Doping Controlled Phase Competition in Ca $_{1 - x}$ Sr $_{x}$ Co $_{2 - y}$ As $_{2}$

arXiv:1904.06444 · doi:10.1103/PhysRevB.100.024415

Abstract

In search of a quantum phase transition between the two-dimensional ( $2$ D) ferromagnetism of CaCo $_{2 - y}$ As $_{2}$ and stripe-type antiferromagnetism in SrCo $_{2}$ As $_{2}$ , we rather find evidence for $1$ D magnetic frustration between magnetic square Co layers. We present neutron diffraction data for Ca $_{1 - x}$ Sr $_{x}$ Co $_{2 - y}$ As $_{2}$ that reveal a sequence of $x$ -dependent magnetic transitions which involve different stacking of $2$ D ferromagnetically-aligned layers with different magnetic anisotropy. We explain the $x$ -dependent changes to the magnetic order by utilizing classical analytical calculations of a $1$ D Heisenberg model where single-ion magnetic anisotropy and frustration of antiferromagnetic nearest- and next-nearest-layer exchange are all composition dependent.

Antiferromagnetic Stacking of Ferromagnetic Layers and Doping Controlled Phase Competition in Ca1−x​Srx​Co2−y​As2​

Abstract

Antiferromagnetic Stacking of Ferromagnetic Layers and Doping Controlled Phase Competition in Ca $_{1 - x}$ Sr $_{x}$ Co $_{2 - y}$ As $_{2}$