Frustrated Garnet Gd3Te2Li3O12 for High-Performance Sub-Kelvin Adiabatic Demagnetization Refrigeration

Abstract

Owing to the limited availability and high cost of 3He, adiabatic demagnetization refrigeration (ADR) has gained considerable attention as an efficient technology for ultralow-temperature applications. Here, we demonstrate the frustrated garnet Gd3Te2Li3O12 (GTLG) as a high-performance ADR material with substantially improved cooling capability over the commercial benchmark Gd3Ga5O12 (GGG). Direct ADR measurements reveal a minimum temperature of 165 mK for GTLG, nearly two-fold lower than that of GGG (320 mK). Under a cryostat bath temperature of 1.8 K, GTLG maintains temperatures below 1 K for more than 12 h and below the 3He-temperature (0.4 K) for over 3 h, demonstrating excellent temperature stability for prolonged cryogenic operation. Magnetic and thermodynamic measurements show that GTLG undergoes antiferromagnetic ordering at TN ∼ 0.25 K while retaining strong magnetic frustration and a large magnetic entropy reservoir favorable for efficient demagnetization cooling. Field-dependent heat capacity and magnetic Grüneisen parameter measurements further reveal the presence of field-induced critical behavior that enables cooling below TN through enhanced entropy accumulation near the critical region. These findings establish GTLG as a promising next-generation magnetic refrigerant and highlight field-induced criticality as an effective design principle for developing advanced materials for ultralow-temperature refrigeration.