How to specify Y-axis Maximum Value in Excel Chart?

I wrote the following code to create a chart in Excel, but I need to specify that the Y Axis 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

So to clarify, if the maximum value the chart needs to draw is about 66 then the Y-axis will by default set itself to 70 but I need it to be 100 regardless.

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