You can try something like this:
k = Graphics[Line[{{-1/4, 1/4}, {0, 0}, {-1/4, -1/4}}]];
Plot[Sin[x], {x, -10, 10},
AxesLabel -> {x, y}, PlotRange -> {-11, 11},
LabelStyle -> Directive[Black, 14, Italic,
FontFamily -> "Times New Roman"],
TicksStyle -> Directive[Black, Plain, 10],
AxesStyle -> Arrowheads[{{Automatic, 0,
Graphics[Line[-{{-1/4, 1/4}, {0, 0}, {-1/4, -1/4}}]]},
{Automatic, Automatic, k}}]]