Magnetoresistance and magnetic phase transitions in a Pr$^{11}$B$_6$ antiferromagnet

In isotopically pure praseodymium hexaboride (Pr¹¹B₆) single-crystal samples, the transverse magnetoresistance Δρ/ρ has been measured in a temperature range of 2–20 K in magnetic fields up to 80 kOe. The field and angular dependences Δρ/ρ(H, ϕ, T ₀) reveal a new magnetic phase in the AFM state of Pr¹¹B₆ which is observable only for the external magnetic field orientation in a narrow angular range near H ‖ ⟨;110⟩. The data remove the previous contradictions in the Pr11B6 magnetic phase diagram representation and can be explained under the assumption that the spin-polarized regions (ferrons) are involved in the formation of the complex magnetic structure in the Pr¹¹B₆ AFM state in the 5d band in the vicinity of the rare-earth ions.