Variation of magnetic ground state ofSr1−xCaxCo2P2determined with

Magnetic properties of the itinerant A- type antiferromagnet CaCo2P2 studied by Co59 and Higa1, Ding2, Teruya3 et al. 2018Phys. Rev. B5000View full textAdd to dashboardCite

“…From the spectrum, the internal magnetic induction |B Co int | for 59 Co is estimated to be 2.0 T at 4.2 K. B Co int is proportional to A hf <µ> where A hf is the hyperfine coupling constant and <µ> is the ordered Co magnetic moment. Using B Co int = -2.0 T where the negative sign is reasonably assumed and A Co ab = (-57.6 ± 4.2) kOe/µ B /Co, <µ> is estimated to be 0.35 µ B which is in good agreement with 0.32 µ B reported by the ND measurement 36 and slightly smaller than 0.4µ B from µSR measurements 51 . Here we used the hyperfine coupling constant for the ab plane direction since the Co moments are in the ab plane as will be shown below.…”

Co-existence of short- and long-range magnetic order in LaCo2P2

“…Another scenario includes by not only considering the spin degree of freedom, but also the lattice degree of freedom. The related compound, Sr 1−x Ca x Co 2 P 2 , could be tuned from a SRO ground state (0.5 < x < 0.7) to a LRO ground state (x ≥ 0.7) [9]. The ground state was found to be correlated to the interplane distance [9], as the substitution of Sr with Ca gradually compresses the unit cell [24].…”

“…The related compound, Sr 1−x Ca x Co 2 P 2 , could be tuned from a SRO ground state (0.5 < x < 0.7) to a LRO ground state (x ≥ 0.7) [9]. The ground state was found to be correlated to the interplane distance [9], as the substitution of Sr with Ca gradually compresses the unit cell [24]. It may be that the interplane distance, or more precisely the interplane interaction, in LaCo 2 P 2 around T ZF C is such that the compound is on the borderline between SRO and LRO, for which one order is favored over the other at lower temperatures.…”

“…It has been observed in several AT 2 P 2 (A = Ca, Sr, and Ba, and T = Fe, Co, and Ni) compounds that the magnetic phase transitions are related to subtle structural changes in the crystals [11,6,12]. These compounds have shown to transform from an uncollapsed tetragonal (ucT) phase to a collapsed tetragonal (cT) phase as a function of chemical doping [6,12,9], which naturally affects the ground state. While the majority of the AT 2 P 2 compounds exhibit AF or PM ground states, LaCo 2 P 2 is an itinerant FM with T ZF C = 135 K. In fact, magnetisation measurements [14,15] satisfy Rhodes-Wohlfarth relation, and the spin fluctuations resembles that of a weak itinerant ferromagnet [16,15].…”

Pressure driven magnetic order in Sr$_{1-x}$Ca$_x$Co$_2$P$_2$

“…A Curie-Weiss behaviour is observed in all compounds at high temperature, but the high temperature fluctuations changes from antiferromagnetic to ferromagentic type around x ∼ 0.5 [10]. Such change seem to be correlated to the finally ground state as it is transformed from paramagnetic (x < 0.45) to antiferromagnteic (AF) at x ≈ 0.5 [11]. In fact, bulk magnetisation measured as a function of x show a clear correlation between the detailed crystalline structure and the magnetic properties [10].…”