Tricritical phenomena in magnetic Wyle semimetals AMnP (A: Zr, Hf)

AMnP (A: Zr, Hf) are recently identified topological nodal line magnetic Wyle semimetals with the topological states protected with vertical mirror symmetry[1]. Their low-temperature Arrott plots were used to confirm the easy axis of magnetization and high-temperature Arrott plots were reported only for ZrMnP before[2]. From the preliminary speculation of data, ZrMNP was identified strictly following mean-field theory in its tricritical exponents whereas HfMnP single crystalline samples exponent data were relatively difficult to access due to smaller crystal sizes and irregular surfaces to perfectly mount on the required surfaces. We will investigate the larger crystal growth techniques for these compounds and investigate further physical properties. In this talk, we will report a comparison of tricritical exponents of Ferro to paramagnetic transition in these systems and investigate the potential role of higher spin-orbit interaction in HfMnP to understand the deviation with ZrMnP if there exist any.