II-VI diluted magnetic semiconductor of Cd1-x-yMnxHgyTe1-zSez crystal (0.1 < x, y < 0.3, 0 less than or equal to z less than or equal to 0.02) has a high Hg vapor pressure at a temperature of crystal growth from a melt and also has temperature-composition phase diagrams with a wide solid solution. A quenched polycrystal ingot starting from a stoichiometric Cd1-x-yMnxHgyTe1-zSez melt was scaled up to a large size (20 mm diameter by 30 mm length) using a high-pressure synthesizing furnace, where a sealed quartz ampoule is subject to a high external pressure of argon gas (e.g. 14.0 MPa at 1060 degrees C). Using this quenched polycrystal ingot, a large oriented single crystal has been grown by the zone melt method (ZM) for the first time. It has a large size (20 mm diameter by 25 mm length), low insertion loss (0.2, dB at 0.98 mu m) and compositional uniformity both in the axial and radial directions.