Preparation of polycrystals with various Tc and single crystal growth of Ba2Ca3Cu4O8(O1−yFy)2 under high pressure

Antiferromagnetic Phase Transition in Four-Layered High-TcSuperconductors Ba2Ca3Cu4O8(FyO1-y)2withTc=55–102 K:63Cu- and19F-NMR Studies

“…It is known as a new family of multilayered copper oxides with apical fluorine. [10][11][12][13] The substitution of oxygen (O À2 ) for apical fluorine (F À1 ), i.e., a decrease in nominal fluorine content ( y), results in the doping of holes into CuO 2 layers, increasing T c from 55 K at y ¼ 1:0 to 102 K at y ¼ 0:6, as shown in Fig. 1(b).…”

“…1(b). 11) This system provides an opportunity to investigate the characteristics of CuO 2 layers over a wide range of carrier densities, enabling us to focus on the interplay of SC and AFM in an underdoped region. [14][15][16][17][18][19][20][21][22] Here, we may note, in passing, that when y ¼ 1:0, the apical fluorine system is a Mott insulator show that the AFM order, which can uniformly coexist with SC, exists up to N h ' 0:15 being a QCP for the four-layered compounds.…”

A63Cu-NMR study on four-layered high-Tcsuperconductors Ba2Ca3Cu4O8(FyO1−y)2

“…, which has four CuO 2 layers, is known as a new family of multilayered copper oxides with apical fluorine [7,8,9]. The substitution of oxygen (O −2 ) for apical fluorine (F −1 ), i.e., a decrease in nominal fluorine content (y), increases T c from 55 K at y = 1.0 to 102 K at y = 0.6 [7].…”

“…The substitution of oxygen (O −2 ) for apical fluorine (F −1 ), i.e., a decrease in nominal fluorine content (y), increases T c from 55 K at y = 1.0 to 102 K at y = 0.6 [7]. Although it is expected that the substitution results in the doping of holes into CuO 2 layers, the actual carrier density has not been clear.…”

Charge Imbalance Effects on Interlayer Hopping and Fermi Surfaces in Multilayered High-TcCuprates

“…Multilayered high-T c cuprates, e.g., Ba 2 Ca 3 Cu 4 O 8 (O 1Ày F y ) 2 1-3) and HgBa 2 Ca 4 Cu 5 O y , [4][5][6] have two kinds of CuO 2 planes in one conducting block; the pyramidally-coordinated-outer-planes (OP's) and the square-coordinated-inner-planes (IP's). Due to spatial variation of Madelung potential, [7][8][9][10] the carrier density in the OP is generally different from that in the IP.…”