边框问题

为什么设定横坐标刻度后上面的刻度就没了
\[CapitalDelta] = 1.66;
s = 1;
s1 = -1;
\[Gamma] = 75*10^(-3);
h = 6.58*^-16;
p = 8.617*10^-5;
\[Mu] = 0.8397209424904093`;
\[Mu]1 = 0.8388894343099993`;
T = 300;
e = Sqrt[1.44 10^-7];
Plot[Re[1/
16 (1/(1 +
E^((-\[Mu] + 1/2 (s \[Gamma] - 2000000000000 h \[Pi] \[Nu]))/(
p T))) - 1/(
1 + E^((-\[Mu] +
1/2 (s \[Gamma] + 2000000000000 h \[Pi] \[Nu]))/(
p T)))) (1 + (-s \[Gamma] + \[CapitalDelta])^2/(
4000000000000000000000000 h^2 \[Pi]^2 \[Nu]^2)) +
1/16 (1/(
1 + E^((-\[Mu]1 +
1/2 (s1 \[Gamma] - 2000000000000 h \[Pi] \[Nu]))/(p T))) - 1/(
1 + E^((-\[Mu]1 +
1/2 (s1 \[Gamma] + 2000000000000 h \[Pi] \[Nu]))/(
p T)))) (1 + (-s1 \[Gamma] + \[CapitalDelta])^2/(
4000000000000000000000000 h^2 \[Pi]^2 \[Nu]^2))], {\[Nu], 0,
750}, PlotRange -> {0, 0.23},
PlotStyle -> {Directive[RGBColor[0.47, 0.47, 0.47], Opacity[1.],
AbsoluteThickness[2]]}, Frame -> True,
FrameTicks -> {Automatic, {{0, 200, 400, 600}, Automatic}}]