Self-biased (EuHoBi)3(FeGa)5O12 garnet films with high coercivity for magnet-free optical isolator

Self-biased magneto-optical single-crystalline garnet materials can eliminate the need for external driving magnetic fields, significantly reducing the size of photonic integrated circuits. In this study, an (EuHoBi)3(FeGa)5O12 single-crystalline film with rectangular magnetic hysteresis loops and self-biased characteristics was successfully grown by liquid-phase epitaxy on the (GdCa)3(ZrMgGa)5O12 (SGGG) substrate. The chemical composition, magnetic properties, and MO performance of the epitaxial film were systematically investigated. One of our as-grown (EuHoBi)3(FeGa)5O12 film exhibited a coercivity of 645 ± 5 Oe, a 100% remanence ratio, and a specific Faraday rotation angle of 1180 °/cm at 1310 nm, combined with an exceptionally low optical loss of merely 0.09 ± 0.03 dB. These findings demonstrate that the epitaxial (EuHoBi)3(FeGa)5O12 single-crystalline film holds great potential for enhancing the integration density of photonic integrated circuits.