Universality of weak ferromagnetism in the magnetically frustrated system R1−xYxB4

Highlighted
• The universality of anomalous weak ferromagnetism was confirmed in nonmagnetic ion substituted RB4.
• The exotic weak ferromagnetism occurred only along the magnetic easy axis.
• The general properties of R1−xYxB4 (R = Sm, Gd, Tb, Dy, and Er) were also confirmed as follows.
• The weak ferromagnetic transition temperature was found to be the same as the antiferromagnetic transition temperature.
• The magnitude of saturated magnetization at T = 2 K has a strong dependence on Y-concentration.

Emergence of anomalous weak ferromagnetism in geometrically frustrated magnetic system of R1−xYxB4 (R = Tb and Dy) is quite interesting [Phys. Rev. B 91, 024414 (2015)]. In order to study the weak ferromagnetism in other compounds, the magnetic properties of R1−xYxB4 (R = Sm, Gd, and Er) were investigated. The anomalous weak ferromagnetism was also found to occur in all compounds, R1−xYxB4 (R = Sm, Gd, and Er). The weak ferromagnetism is revealed in the magnetic easy plane, (001), for R1−xYxB4 (R = Sm and Gd) and along the magnetic easy axis, [001], for R1−xYxB4 (R = Er). The magnitude of saturated magnetic moment at T = 2 K shows a strong dependence on Y-concentration, i.e., the maximum magnitude occurs at x ≈ 0.3 for all compounds. The general magnetic properties of weak ferromagnetism is quite similar to the weak ferromagnetism in R1−xYxB4 (R = Tb, Dy). Therefore, it is experimentally demonstrated that the emergence of weak ferromagnetism, induced by non-magnetic substitution in a magnetically frustrated system, is the universal feature in RB4 compounds.