Excel Chart Axis Maximum Fixed Value

I've wrote the following code to create a chart in Excel, but I need to specify the Y Axis to be fixed at 100 instead of set to the default of Auto.

# Generate graph
$xRow = 1
$yRow = $rows
$objRange=$Worksheet.range("a${xRow}:c${yRow}")
$colCharts=$excel.Charts
$objChart=$colCharts.Add()
$objChart.ChartType=4
$objChart.Axes(0).CategoryType=2
$objChart.Axes(0).TickLabelSpacing=7
$objChart.HasTitle = $true
$objChart.ChartTitle.text = "Report"
$a=$objChart.Activate

I've tried $objChart.Axes(0).Maximum = 100 and also .Minimum and .MaximumScaling and .Scaling.Maximum but none of these have worked. Does anyone know the correct command?

Thanks in advance