Magnetic properties of exchange-enhanced Pauli paramagnetic metals AeCo2P2 (Ae = Sr, Ba)

We have synthesized single crystals of AeCo2P2 (Ae = Sr, Ba) and polycrystalline powder sample of Sr1−x Ba x Co2P2, and measured their magnetic properties. SrCo2P2 shows an itinerant-electron metamagnetic transition at Hc = 600 kOe and its temperature dependent magnetic susceptibility shows characteristic two anomalies at T max1 = 25 and T max2 = 115 K, suggesting it is in the vicinity of a ferromagnetic quantum critical point. While, BaCo2P2 does not show the metamagnetic transition with the applied field up to 600 kOe, and its magnetic susceptibility shows only one anomaly corresponding to T max1 at 33 K. In addition, the Weiss temperature of Sr1−x Ba x Co2P2, decreases to negative as x increases. These results indicate the system recede from the quantum critical point by the Ba substitution.