Anomalous Antiferromagnetic Properties of the Tetragonal Compound, TbB₂C₂

Specific heat and magnetic phase diagram of Tb1−xGdxB2C2

“…The C(T) of x ¼ 0 shows a sharp l-type peak at T N ¼ 21.7 K as reported in the previous work [3]. On the other hand, C(T) of x ¼ 0.1 has two anomalies: a shoulder at T 1 ¼ 11.5 K and a l-type peak at T N ¼ 21.7 K which is considerably broadened comparing with that of x ¼ 0.…”

“…The (1 0 1/2) propagation vector in phase IV is peculiar to TbB 2 C 2 since the other RB 2 C 2 such as R ¼ Gd [4] or Dy [1] exhibit (1 0 0)-type AFM structure. Furthermore, the magnetic susceptibility anomalously increases below T N without any spontaneous magnetization [3]. These anomalous behaviors imply that the AFM state of TbB 2 C 2 is affected by multipolar interactions besides magnetic one.…”

“…In this system, TbB 2 C 2 shows an antiferromagnetic (AFM) ordering at T N ¼ 21.7 K with the main (1 0 1/2) propagation vector and field-induced antiferroquadrupolar (AFQ) transition [3]. The AFM phase in TbB 2 C 2 that has been called phase IV shows some anomalous features in its magnetic behavior.…”

“…Tetragonal compounds RB 2 C 2 (R ¼ rare-earth metals) show the variety of magnetic properties due to the coexistence and competition between magnetic and quadrupolar interactions [1][2][3]. In this system, TbB 2 C 2 shows an antiferromagnetic (AFM) ordering at T N ¼ 21.7 K with the main (1 0 1/2) propagation vector and field-induced antiferroquadrupolar (AFQ) transition [3].…”

Unusual antiferromagnetic properties affected by antiferroquadrupolar interaction in TbB2C2

“…An AFQ order in HoB 2 C 2 coexists with an AFM order below T Q ¼ 4:5 K [2]. For TbB 2 C 2 ; an AFM order realizes at T N ¼ 21:7 K [3]. The effect of AFQ interaction in TbB 2 C 2 becomes prominent by applying external magnetic fields.…”