Absence of magnetic ordering in the spin liquid candidate Ca₃Cu₂GeV₂O₁₂

Abstract

Typically, quantum spin liquid candidates can be found in materials with a combination of geometrical frustration along with low spin. Due to its spin of S = 1/2 the copper (II) ion is often present in the discussion on spin liquid candidates. The solid state compound Ca 3 Cu 2 GeV 2 O 12 is a material that crystallizes in the garnet structure (s.g. #230, Ia3d), where 3D frustration is known to occur. Heat capacity has shown a lack of magnetic ordering down to 0.35 K, confirmed with low temperature neutron diffraction to 0.07 K. This system displays a Weiss temperature of −0.93(1) K indicating net antiferromagnetic interactions and significant J 1 -J 2 competition causing frustration. Using both neutron and xray diffraction along with heat capacity and magnetometry, the work presented here shows Ca 3 Cu 2 GeV 2 O 12 has potential as a new spin liquid candidate.