Lanthanum boride type single crystal and method for growing the same

• US 5,238,527 A
• Filed: 05/28/1991
• Issued: 08/24/1993
• Est. Priority Date: 07/19/1990
• Status: Expired due to Fees

• Current Assignee: National Institute for Research in Inorganic Materials
• Original Assignee: National Institute for Research in Inorganic Materials
• Inventors: Otani, Shigeki, Ishizawa, Yoshio, Tanaka, Takaho
• Primary Examiner(s): Kunemund, Robert
• Assistant Examiner(s): HITESHEW, FELISA CARLA
• Application Number:
  US07/706,197
• Time in Patent Office: 819 Days
• Field of Search: 156/604, 156/615, 156/DIG. 63, 156/DIG. 89
• US Class Current: 117/42
• CPC Class Codes: C30B 13/00 Single-crystal growth by zone-melting; Refining by zone-melting C30B17/00 takes precedence; by changing the cross-section of the treated solid C30B15/00; under a protective fluid C30B27/00; for the growth of homogeneous polycrystalline material with defined structure C30B28/00
• CPC Class Codes: C30B 29/10 Inorganic compounds or compositions

Abstract

The present invention relates to a lanthanum boride type single crystal having the chemical formula (La_1-x M_x)B₆ (0.01≦x≦0.50) wherein M is at least one rare earth element selected from the group consisting of Ce, Pr, Nd, Sm and Gd, and further relates to a method for growing a lanthanum boride type single crystal by fusion method, which comprises using a lanthanum boride starting material containing from 1 to 50 mol % of at least one rare earth boride selected from the group consisting of CeB₆, PrB₆, NdB₆, SmB₆ and GdB₆.

Claims

1. A method for growing a single crystal having a chemical formula (La_1-x M_x)B₆, (0.01 ≦

x≦

0.5) by fusion method, which comprises using a lanthanum boride starting material containing from 1 to 50 mol % of at least one rare earth hexaboride selected from the group consisting of CeB₆, PrB₆, NdB₆, SmB₆ and GdB₆.

2. The method according to claim 1, wherein the growing speed is from 0.2 cm to 5 cm/hr.

3. The method according to claim 1, wherein the growing is carried out in an inert atmosphere of argon or helium.

4. The method according to claim 1, wherein the rare earth boride is replaced by a mixture of boron with at least one member selected from the group consisting of rare earth oxide, rare earthhydroxide and rare earth chloride at such a predetermined ratio as to provide a rare earth hexa-boride.

5. The method according to claim 4, wherein the growing speed is from 0.2 cm to 5 cm/hr.

6. The method according to claim 4, wherein the growing is carried out in an inert atmosphere of argon or helium.