The emergence of Griffiths phase in CaCu 3 Ti (4− x ) Mn x O 12 (CCTMO, x = 1, 2 and 3) geometrically frustrated antiferromagnetic complexes perovskite

In this work, we have reported the rare coexistence of a Griffiths phase (GP) in a complex perovskite oxide with geometrically frustrated antiferromagnetism. We have achieved this by substituting Manganese (Mn) in the titanium site of CaCu3Ti (4− x ) MnxO 12 (CCTMO, x = 1, 2 and 3). The occurrence of a Griffiths phase is observed when a strong contest between antiferromagnetic transition (TN) and paramagnetic (PM) occurs in the magnetic domain. As we increased the molar concentration of Manganese while substituting at titanium site in CaCu 3 Ti 4 O 12 , we observed the appearance of a step-like Griffiths phase. Manganese (Mn)-substituted materials exhibit paramagnetic (PM) to ferromagnetic (FM) phase transitions below CaCu 3 Ti 3 Mn 1 O 12 (CCTM 1 O), CaCu 3 Ti 2 Mn 2 O 12 (CCTM 2 O), and CaCu 3 Ti 1 Mn 3 O 12 (CCTM 3 O), marked by a rapid step-like change in the magnetic moment due to spin ordering. The deviation of inverse magnetic susceptibility (χ −1 ) from Curie–Weiss behavior occurs in the temperature ranges of 75 to 190 K, 80 to 200 K, and 150 to 280 K, respectively. The emergence of the Griffiths phase before the actual PM–FM transition indicates that the inhomogeneous phase above the Curie temperature ( T C ), which can be defined as a Griffiths phase, is dominated by ferromagnetic interactions rather than antiferromagnetic ones. The presence of a Griffiths-like phase beyond its Curie temperature ( T C ) is indicated by low-field DC magnetization of the nanostructures, showing abnormal magnetic behavior. The presence of short-range magnetic correlations and ferromagnetic clusters in the system due to the size decrease is linked to this unexpected behaviour.