Magnetic anisotropy of the low-temperature specific heat of Ho$_{0.01}$Lu$_{0.99}$B$_{12}$ with dynamic charge stripes

The specific heat of Ho$_{0.01}$Lu$_{0.99}$B$_{12}$ single crystals with dynamic charge stripes is studied at low and ultralow temperatures (0.07–20 K) in applied magnetic fields of 0–9 T. It is shown that additional contributions to the specific heat appear at magnetic fields exceeding 1 T. These contributions depend on the orientation of the magnetic field and can be as large as 15% of the specific heat related to the subsystem of holmium ions in the cubic crystal field.